1. Musculoskeletal System

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Authors: Dahnert, Wolfgang

Title: Radiology Review Manual, 6th Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Musculoskeletal System

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Musculoskeletal System

Differential Diagnosis of Musculoskeletal Disorders

Differential-Diagnostic Gamut of Bone Disorders

Conditions to be considered = dissect bone disease with a DIATTOM

  • Dysplasia + Dystrophy

  • Infection

  • Anomalies of development

  • Tumor + tumorlike conditions

  • Trauma

  • Osteochondritis + ischemic necrosis

  • Metabolic disease

DYSPLASIA = disturbance of bone growth
DYSTROPHY = disturbance of nutrition

Limping child

1 4 Years

  • CONGENITAL

    • Developmental dysplasia of hip

  • TRAUMATIC

    • Toddler's fracture

    • Nonaccidental trauma

    • Other fractures

    • Foreign body

  • INFLAMMATORY

    • Diskitis

    • Septic arthritis

    • Osteomyelitis

    • Transient synovitis of hip

4 10 Years

  • TRAUMATIC

  • INFLAMMATORY

    • Septic arthritis

    • Osteomyelitis

    • Transient synovitis of hip

    • Diskitis

    • Juvenile rheumatoid arthritis

  • VASCULAR

    • Legg-Perthes disease

10 15 Years

  • TRAUMATIC

    • Stress fracture

    • Osteochondritis dissecans

    • Osgood-Schlatter disease

  • INFLAMMATORY

    • Juvenile rheumatoid arthritis

    • Ankylosing spondylitis

    • Septic arthritis

    • Osteomyelitis

  • HORMONAL

    • Epiphyseolysis of femoral head

Delayed bone age

  • CONSTITUTIONAL

    • Familial

    • IUGR

  • METABOLIC

    • Hypopituitarism

    • Hypothyroidism

    • Hypogonadism (Turner syndrome)

    • Cushing disease, steroid therapy

    • Diabetes mellitus

    • Rickets

    • Malnutrition

    • Irradiation of brain (for cerebral tumor / ALL)

  • SYSTEMIC DISEASE

    • Congenital heart disease

    • Renal disease

    • GI disease: celiac disease, Crohn disease, ulcerative colitis

    • Anemia

    • Bone marrow transplantation (<5 years of age)

  • SYNDROMES

    • Trisomies

    • Noonan disease

    • Cornelia de Lange syndrome

    • Cleidocranial dysplasia

    • Lesch-Nyhan disease

    • Metatrophic dwarfism

Bone sclerosis

Diffuse Osteosclerosis

mnemonic: 5 M'S To PROoF

  • Metastases

  • Myelofibrosis

  • Mastocytosis

  • Melorheostosis

    Metabolic: hypervitaminosis D, fluorosis, hypothyroidism, phosphorus poisoning

  • Sickle cell disease

  • Tuberous sclerosis

  • Pyknodysostosis, Paget disease

  • Renal osteodystrophy

  • Osteopetrosis

  • Fluorosis

Constitutional Sclerosing Bone Disease

  • Engelmann-Camurati disease

  • Infantile cortical hyperostosis

  • Melorheostosis

  • Osteopathia striata

  • Osteopetrosis

  • Osteopoikilosis

  • Pachydermoperiostosis

  • Pyknodysostosis

  • Van Buchem disease

    • P.2


  • Williams syndrome

Sclerosing Bone Dysplasia

  • Dysplasias of ENDOCHONDRAL OSSIFICATION (PRIMARY SPONGIOSA)

    • = failure in resorption + remodeling of primary immature spongiosa by osteoclasts

    • accumulation of calcified cartilage matrix packing the medullary cavit

    Target sites: tubular + flat bones, vertebrae, skull base, ethmoids, ends of clavicle

    • Osteopetrosis

    • Pyknodysostosis

  • Dysplasias of ENDOCHONDRAL OSSIFICATION (SECONDARY SPONGIOSA)

    • = errors in resorption + remodeling of secondary spongiosa

    • focal densities / striations

    • Enostosis

    • Osteopoikilosis

    • Osteopathia striata

  • Dysplasias of INTRAMEMBRANOUS OSSIFICATION

    • = disequilibrium between periosteal bone formation + endosteal bone resorption

      Target sites: cortex of tubular + flat bones, calvaria, bones of upper face, tympanic parts of temporal bone, vomer, medial pterygoid

    • Progressive diaphyseal dysplasia

    • Hereditary multiple diaphyseal sclerosis (Ribbing disease)

    • Hyperostosis corticalis generalisata

      • Van Buchem disease

      • Sclerosteosis (Truswell-Hansen disease)

      • Worth disease

      • Nakamura disease

    • Diaphyseal dysplasia with anemia

    • Oculodento-osseous dysplasia

    • Trichodento-osseous dysplasia

    • Kenny-Caffey syndrome

  • MIXED SCLEROSING DYSPLASIAS

    • predominantly endochondral disturbance

      • Dysosteosclerosis

      • Metaphyseal dysplasia (Pyle disease)

      • Craniometaphyseal dysplasia

      • Frontometaphyseal dysplasia

    • predominantly intramembranous defects

      • Melorheostosis

      • Craniodiaphyseal dysplasia

      • Lenz-Majewski hyperostotic dwarfism

      • Progressive diaphyseal dysplasia

Solitary Osteosclerotic Lesion

  • DEVELOPMENTAL

    • Bone island

  • VASCULAR

    • Old bone infarct

    • Aseptic / ischemic / avascular necrosis

  • HEALING BONE LESION

    • trauma: callus formation in stress fracture

    • benign tumor: fibrous cortical defect / nonossifying fibroma, brown tumor; bone cyst

    • malignant tumor: lytic metastasis after radiation, chemo-, hormone therapy

  • INFECTION / INFLAMMATION

    (low-grade chronic infection / healing infection)

    • Osteoid osteoma

    • Chronic / healed osteomyelitis: bacterial, tuberculous, fungal

    • Sclerosing osteomyelitis of Garr

    • Granuloma

    • Brodie abscess

  • BENIGN TUMOR

    • Osteoma

    • Osteoblastoma

    • Ossifying fibroma

    • Healed fibrous cortical defect

    • Enchondroma / osteochondroma

  • MALIGNANT TUMOR

    • Osteoblastic metastasis (prostate, breast)

    • Lymphoma

    • Sarcoma: osteo-, chondro-, Ewing sarcoma

  • OTHERS

    • Sclerotic phase of Paget disease

    • Fibrous dysplasia

Cortical Sclerotic Lesion in Child

  • Osteoid osteoma

  • Stress fracture

  • Chronic osteomyelitis

  • Healed fibrous cortical defect

Multiple Osteosclerotic Lesions

  • FAMILIAL

    • Osteopoikilosis

    • Enchondromatosis = Ollier disease

    • Melorheostosis

    • Multiple osteomas: associated with Gardner syndrome

    • Osteopetrosis

    • Pyknodysostosis

    • Osteopathia striata

    • Chondrodystrophia calcificans congenita= congenital stippled epiphyses

    • Multiple epiphyseal dysplasia = Fairbank disease

  • SYSTEMIC DISEASE

    • Mastocytosis = urticaria pigmentosa

    • Tuberous sclerosis

Bone-within-bone Appearance

= endosteal new bone formation

  • Normal

    • thoracic + lumbar vertebrae (in infants)

    • growth recovery lines (after infancy)

  • Infantile cortical hyperostosis (Caffey)

  • Sickle cell disease / thalassemia

  • Congenital syphilis

  • Osteopetrosis / oxalosis

  • Radiation

  • Acromegaly

  • Paget disease

  • Gaucher disease

P.3


mnemonic: BLT PLT RSD RSD

  • Bismuth ingestion

  • Lead ingestion

  • Thorium ingestion

  • Petrosis (osteopetrosis)

  • Leukemia

  • Tuberculosis

  • Rickets

  • Scurvy

  • Dtoxicity (vitamin D)

  • RSD (reflex sympathetic dystrophy)

Dense Metaphyseal Bands

mnemonic: DENSE LINES

  • D-vitamin intoxication

  • Elemental arsenic and heavy metals (lead, bismuth, phosphorus)

  • Normal variant

  • Systemic illness

  • Estrogen to mother during pregnancy

  • Leukemia

  • Infection (TORCH), Idiopathic hypercalcemia

  • Never forget healed rickets

  • Early hypothyroidism (cretinism)

  • Scurvy, congenital Syphilis, Sickle cell disease

    also: methotrexate therapy

Osteopenia

= decrease in bone quantity maintaining normal quality

  • increased radiolucency of bone:

    • vertical striations in vertebral bodies

    • accentuation of tensile + compressive trabeculae of proximal femur

    • reinforcement lines (= bone bars) crossing marrow cavity about knee

    • cortical resorption of 2nd metacarpal:

      • measuring outer cortical diameter (W) and width of medullary cavity (m) at midportion of bone and reporting combined cortical thickness (CCT)

    • subperiosteal tunneling

Categories:

  • DIFFUSE OSTEOPENIA

    • Osteoporosis = decreased osteoid production

    • Osteomalacia = undermineralization of osteoid

    • Hyperparathyroidism

    • Multiple myeloma / diffuse metastases

    • Drugs

    • Mastocytosis

    • Osteogenesis imperfecta

  • REGIONAL OSTEOPENIA

Osteoporosis

= reduced bone mass of normal composition secondary to

  • osteoclastic resorption (85%) (trabecular, endosteal, intracortical, subperiosteal)

  • osteocytic resorption (15%)

Incidence: 7% of all women aged 35 40 years; 1 in 3 women > age 65 years

Etiology:

  • CONGENITAL DISORDERS

    • Osteogenesis imperfecta

      • The only osteoporosis with bending!

    • Homocystinuria

  • IDIOPATHIC (bone loss begins earlier + proceeds more rapidly in women)

    1. Juvenile osteoporosis: <20 years
    2. Adult osteoporosis: 20 40 years
    3. Postmenopausal osteoporosis: >50 years (40 50% lower trabecular bone mineral density in elderly than in young women)
    4. Senile osteoporosis: >60 years progressively decreasing bone density at a rate of 8% in females; 3% in males

  • NUTRITIONAL DISTURBANCES

    • scurvy; protein deficiency (malnutrition, nephrosis, chronic liver disease, alcoholism, anorexia nervosa, kwashiorkor, starvation), calcium deficiency

  • ENDOCRINOPATHY

    • Cushing disease, hypogonadism (Turner syndrome, eunuchoidism), hyperthyroidism, hyperparathyroidism, acromegaly, Addison disease, diabetes mellitus, pregnancy, paraneoplastic phenomenon in liver tumors

  • RENAL OSTEODYSTROPHY

    • decrease / same / increase in spinal trabecular bone; rapid loss in appendicular skeleton

  • IMMOBILIZATION = disuse osteoporosis

  • COLLAGEN DISEASE, RHEUMATOID ARTHRITIS

  • BONE MARROW REPLACEMENT

    • infiltration by lymphoma / leukemia (ALL), multiple myeloma, diffuse metastases, marrow hyperplasia secondary to hemolytic anemia

  • DRUG THERAPY

    • heparin (15,000 30,000 U for >6 months), methotrexate, corticosteroids, excessive alcohol consumption, smoking, Dilantin

  • RADIATION THERAPY

  • LOCALIZED OSTEOPOROSIS

    • Sudeck dystrophy, transient osteoporosis of hip, regional migratory osteoporosis of lower extremities

  • serum calcium, phosphorus, alkaline phosphatase frequently normal

  • hydroxyproline may be elevated during acute stage

Technique:

  • SINGLE-PHOTON ABSORPTIOMETRY

    • measures primarily cortical bone of appendicular bones, single-energy I-125 radioisotope source

      Site: distal radius (= wrist bone density), os calcis
      Dose: 2 3 mrem
      Precision: 1 3%

  • DUAL-PHOTON ABSORPTIOMETRY

    • radioactive energy source with two photon peaks; should be reserved for patients <65 years of age because of interference from osteophytosis + vascular calcifications

      Site: vertebrae, femoral neck
      Dose: 5 10 mrem
      Precision: 2 4%

  • SINGLE X-RAY ABSORPTIOMETRY

    • = area projectional technique for quantitative bone density measurement

      P.4


      Site: distal radius, calcaneus
      Dose: low
      Precision: 0.5 2%

  • DUAL ENERGY X-RAY ABSORPTIOMETRY (DEXA)

    • Most widely used & most precise technique!

    • = quantitative digital radiography

    • = beams with two distinct energy levels allow identification of trabecular from cortical bone

    • has replaced dual-photon absorptiometry and is produced by x-ray tube with higher radiation flux than radioisotope source

    Site: lumbar spine, femoral neck, whole body, forearm
    Dose: <3 mrem; Precision: 1 2%

    Data collected:

    • BMD (bone marrow density) value (g/cm2)

    • %BMD compared to young adults

    • %BMD compared to age-matched adults

    • T-score (SD of young-adult mean)

    • Z-score (SD of age-matched mean)

  • QUANTITATIVE COMPUTED TOMOGRAPHY

    • = determines true volumetric density (mg/cm3)

    • high-turnover cancellous bone is important for vertebral strength and has high responsiveness

    • trabecular bone + low-turnover compact bone can be measured separately

    • compared to external bone mineral reference phantom scanned simultaneously with patient to calibrate CT attenuation measurements

    • 10-mm thick section with gantry angle correction through center of vertebral body

      Site: vertebrae L1 L3, other sites
      Use: assessment of vertebral fracture risk; measurement of age-related bone loss; follow-up of osteoporosis + metabolic bone disease
      (a) single energy: 300 500 mrem; 6 25% precision
      (b) dual energy: 750 800 mrem;5 10% precision

    • Most sensitive technique!

  • PERIPHERAL QUANTITATIVE CT

    = exact 3-dimensional localization of target volumes with multisection data acquisition capability covering a large volume of bone

    Site: distal radius
    Location: axial skeleton (lower dorsal + lumbar spine), proximal humerus, neck of femur, wrist, ribs

    • Radiographs are insensitive prior to bone loss of 25 30%

    • Bone scans do NOT show a diffuse increase in activity

      DEXA Interpretation

      Diagnosis T-score Management Follow-up
      Normal >1 prevention 3 years
      Osteopenia <-1 and >-2.5 prevention or therapy 2 years
      Osteopororis <-2.5 therapy 1 year

    • decreased number + thickness of trabeculae

    • cortical thinning (endosteal + intracortical resorption)

    • juxtaarticular osteopenia with trabecular bone predominance

    • delayed fracture healing with poor callus formation

    • (DDx: abundant callus formation in osteogenesis imperfecta + Cushing syndrome)

      Cx: (1) Fractures at sites rich in labile trabecular bone (eg, vertebrae, wrist) in postmenopausal osteoporosis
      (2) Fractures at sites containing cortical + trabecular bone (eg, hip) in senile osteoporosis
      Rx: calcitonin, sodium fluoride, diphosphonates, parathyroid hormone supplements, estrogen replacement

Osteoporosis of Spine

  • diminished radiographic density

  • vertical striations (= marked thinning of transverse trabeculae with relative accentuation of vertical trabeculae along lines of stress)

  • accentuation of endplates

  • picture framing (= accentuation of cortical outline with preservation of external dimensions secondary to endosteal + intracortical resorption)

  • compression deformities with protrusion of intervertebral disks:

    • biconcave vertebrae

    • Schmorl nodes

    • wedging

    • decreased height of vertebrae

  • absence of osteophytes

Osteomalacia

= accumulation of excessive amounts of uncalcified osteoid with bone softening + insufficient mineralization of osteoid due to

  • high remodeling rate: excessive osteoid formation + normal / little mineralization

  • low remodeling rate: normal osteoid production + diminished mineralization

Etiology:

  • dietary deficiency of vitamin D3 + lack of solar irradiation

  • deficiency of metabolism of vitamin D:

    • chronic renal tubular disease

    • chronic administration of phenobarbital (alternate liver pathway)

    • diphenylhydantoin (interferes with vitamin D action on bowel)

  • decreased absorption of vitamin D:

    • malabsorption syndromes (most common)

    • partial gastrectomy (self-restriction of fatty foods)

  • decreased deposition of calcium in bone

    • diphosphonates (for treatment of Paget disease)

Histo: excess of osteoid seams + decreased appositional rate

  • bone pain / tenderness; muscular weakness

  • serum calcium slightly low / normal

  • decreased serum phosphorus

  • elevated serum alkaline phosphatase

P.5


  • uniform osteopenia

  • fuzzy indistinct trabecular detail of endosteal surface

  • coarsened frayed trabeculae decreased in number + size

  • thin cortices of long bone

  • bone deformity from softening:

    • hourglass thorax

    • bowing of long bones

    • acetabular protrusion

    • buckled / compressed pelvis

    • biconcave vertebral bodies

  • increased incidence of insufficiency fractures

  • pseudofractures = Looser zones

  • mottled skull

Localized / Regional Osteopenia

  • Disuse osteoporosis / atrophy

    Etiology: local immobilization secondary to

    • fracture (more pronounced distal to fracture site)

    • neural paralysis

    • muscular paralysis

  • Reflex sympathetic dystrophy = Sudeck dystrophy

  • Regional migratory osteoporosis, transient regional osteoporosis of hip

  • Rheumatologic disorders

  • Infection: osteomyelitis, tuberculosis

  • Osteolytic tumor

  • Lytic phase of Paget disease

  • Early phase of bone infarct and hemorrhage

  • Burns + frostbite

Bone Marrow Edema

= hypointense on T1WI + hyperintense on T2WI relative to fatty marrow

  • Trauma

    • bone bruise

    • radiographically occult acute fracture

    • recent surgery

  • Infection = osteomyelitis

  • Aseptic arthritis

  • Osteonecrosis = early stage of AVN

  • Neuropathic osteoarthropathy

  • Reflex sympathetic dystrophy (some cases)

  • Transient osteoporosis of hip

  • Infiltrative neoplasm

Transverse Lucent Metaphyseal Lines

mnemonic: LINING

  • Leukemia

  • Illness, systemic (rickets, scurvy)

  • Normal variant

  • Infection, transplacental (congenital syphilis)

  • Neuroblastoma metastases

  • Growth lines

Frayed Metaphyses

mnemonic: CHARMS

  • Congenital infections (rubella, syphilis)

  • Hypophosphatasia

  • Achondroplasia

  • Rickets

  • Metaphyseal dysostosis

  • Scurvy

Bone tumor

Role of Radiologist

  • Is there a lesion?

  • Is it a bone tumor?

  • Is the tumor benign or malignant?

  • Is a biopsy necessary?

  • Is the histologic diagnosis consistent with the radiographic image?

Assessment of Aggressiveness

  • BENIGN

    • Diagnosis certain: no further work-up necessary

    • Asymptomatic lesion with highly probable benign diagnosis may be followed clinically

    • Symptomatic lesion with highly probable benign diagnosis may be treated without further work-up

  • CONFUSING LESION

    • not clearly categorized as benign or malignant; needs staging work-up

  • MALIGNANT: needs staging work-up

    Staging work-up:  
    Bone scan: identifies polyostotic lesions (eg, multiple myeloma, metastatic disease, primary osteosarcoma with bone-forming metastases, histiocytosis, Paget disease)
    Chest CT: identifies metastatic deposits + changes further work-up and therapy

Local staging with MR imaging:

  • Margins: encapsulated / infiltrating

  • Compartment: intra- / extracompartmental

  • Intraosseous extent + skip lesions

  • Soft-tissue extent (DDx: hematoma, edema)

  • Joint involvement

  • Neurovascular involvement

Local assessment with CT imaging:

  • matrix / rim calcifications

Tumorlike Conditions

  • Solitary bone cyst

  • Juxtaarticular ( synovial ) cyst

  • Aneurysmal bone cyst

  • Nonossifying fibroma; cortical defect; cortical desmoid

  • Eosinophilic granuloma

  • Reparative giant cell granuloma

  • Fibrous dysplasia (monostotic; polyostotic)

  • Myositis ossificans

  • Brown tumor of hyperparathyroidism

  • Massive osteolysis

Pseudomalignant Appearance

  • Osteomyelitis

  • Aggressive osteoporosis

Pattern of Bone Destruction

  • GEOGRAPHIC BONE DESTRUCTION

    P.6


    Cause: (a) slow-growing usually benign tumor
    (b)rarely malignant: plasma cell myeloma, metastasis
    (c) infection: granulomatous osteomyelitis

    • well-defined smooth / irregular margin

    • short zone of transition

  • MOTH-EATEN BONE DESTRUCTION

    Cause: (a) rapidly growing malignant bone tumor
    (b) osteomyelitis

    • less well defined / demarcated lesional margin

    • longer zone of transition

    mnemonic: H LEMMON

    • Histiocytosis X

    • Lymphoma

    • Ewing sarcoma

    • Metastasis

    • Multiple myeloma

    • Osteomyelitis

    • Neuroblastoma

  • PERMEATIVE BONE DESTRUCTION

    Cause: aggressive bone tumor with rapid growth potential (eg, Ewing sarcoma)

    • poorly demarcated lesion imperceptibly merging with uninvolved bone

    • long zone of transition

Size, Shape, and Margin of Bone Lesion

  • Primary malignant tumors are larger than benign tumors

  • elongated lesion (= greatest diameter of >1.5 times the least diameter): Ewing sarcoma, histiocytic lymphoma, chondrosarcoma, angiosarcoma

  • sclerotic margin (= reaction of host tissue to tumor)

Tumor Position in Transverse Plane

  • CENTRAL MEDULLARY LESION

    • Enchondroma

    • Solitary bone cyst

  • ECCENTRIC MEDULLARY LESION

    • Giant cell tumor

    • Osteogenic sarcoma, chondrosarcoma, fibrosarcoma

    • Chondromyxoid fibroma

  • CORTICAL LESION

    • Nonossifying fibroma

    • Osteoid osteoma

  • PERIOSTEAL / JUXTACORTICAL LESION

    • Juxtacortical chondroma / osteosarcoma

    • Osteochondroma

    • Parosteal osteogenic sarcoma

Tumor Position in Longitudinal Plane

  • EPIPHYSEAL LESION

    • Chondroblastoma (prior to closure of growth plate)

    • Intraosseous ganglion, subchondral cyst

    • Giant cell tumor (originating in metaphysis)

    • Clear cell chondrosarcoma

    • Fibrous dysplasia

    • Abscess

    mnemonic: CAGGIE

    • Chondroblastoma

    • Aneurysmal bone cyst

    • Giant cell tumor

    • Geode

    • Infection

    • Eosinophilic granuloma

      • [after 40 years of age throw out CEA and insert metastases / myeloma]

  • METAPHYSEAL LESION

    • Nonossifying fibroma (close to growth plate)

    • Chondromyxoid fibroma (abutting growth plate)

    • Solitary bone cyst

    • Osteochondroma

    • Brodie abscess

    • Osteogenic sarcoma, chondrosarcoma

  • DIAPHYSEAL LESION

    • Round cell tumor (eg, Ewing sarcoma)

    • Nonossifying fibroma

    • Solitary bone cyst

    • Aneurysmal bone cyst

    • Enchondroma

    • Osteoblastoma

    • Fibrous dysplasia

    mnemonic: FEMALE

    • Fibrous dysplasia

    • Eosinophilic granuloma

    • Metastasis

    • Adamantinoma

    • Leukemia, Lymphoma

    • Ewing sarcoma

Tumors Localizing to Hematopoietic Marrow

  • Metastases

  • Plasma cell myeloma

  • Ewing sarcoma

  • Histiocytic lymphoma

Diffuse Bone Marrow Abnormalities in Childhood

  • REPLACED BY TUMOR CELLS

    • metastatic disease

      • Neuroblastoma (in young child)

      • Lymphoma (in older child)

      • Rhabdomyosarcoma (in older child)

    • primary neoplasm

      • Leukemia

  • REPLACED BY RED CELLS

    • = Red cell hyperplasia = reconversion

      • severe anemia: sickle cell disease, thalassemia, hereditary spherocytosis

      • chronic severe blood loss

      • marrow replacement by neoplasia

      • treatment with granulocyte-macrophage colony stimulating factor

  • REPLACED BY FAT

    • Myeloid depletion = aplastic anemia

  • REPLACED BY FIBROUS TISSUE

    • Myelofibrosis

Age Incidence of Malignant Bone Tumors

  • 80% of bone tumors are correctly determined on the basis of age alone!

P.7


Sarcomas by Age

mnemonic: Every Other Runner Feels Crampy Pain On Moving
Ewing sarcoma 0 10 years
Osteogenic sarcoma 10 30 years
Reticulum cell sarcoma 20 40 years
Fibrosarcoma 20 40 years
Chondrosarcoma 40 50 years
Parosteal sarcoma 40 50 years
Osteosarcoma 60 70 years
Metastases 60 70 years

Age Incidence of Malignant Bone Tumors

Age [years] Tumor
0.1 Neuroblastoma
0.1 10 Ewing tumor in tubular bones (diaphysis)
10 30 Osteosarcoma (metaphysis); Ewing tumor in flat bones
30 40 Reticulum cell sarcoma (similar histology to Ewing tumor); fibrosarcoma; malignant giant cell tumor (similar histology to fibrosarcoma); parosteal sarcoma; lymphoma
>40 Metastatic carcinoma; multiple myeloma; chondrosarcoma

Round Cell Tumors

  • arise in midshaft

  • osteolytic lesion

  • reactive new bone formation

  • no tumor new bone

mnemonic: LEMON

  • Leukemia, Lymphoma

  • Ewing sarcoma, Eosinophilic granuloma

  • Multiple myeloma

  • Osteomyelitis

  • Neuroblastoma

Malignancy with Soft-tissue Involvement

mnemonic: My Mother Eats Chocolate Fudge Often

  • Metastasis

  • Myeloma

  • Ewing sarcoma

  • Chondrosarcoma

  • Fibrosarcoma

  • Osteosarcoma

Tumor Matrix of Bone Tumors

Cartilage-forming Bone Tumors

  • centrally located ringlike / flocculent / flecklike radiodensities

  • BENIGN

    • Enchondroma

    • Parosteal chondroma

    • Chondroblastoma

      Average Age for Occurrence of Benign and Malignant Bone Tumors

      • P.8


    • Chondromyxoid fibroma

    • Osteochondroma

  • MALIGNANT

    • Chondrosarcoma

    • Chondroblastic osteosarcoma

Bone-forming Tumors

  • inhomogeneous / homogeneous radiodense collections of variable size + extent

  • BENIGN

    • Osteoma

    • Osteoid osteoma

    • Osteoblastoma

    • Ossifying fibroma

  • MALIGNANT

    • Osteogenic sarcoma

Fibrous Connective Tissue Tumors

  • BENIGN FIBROUS BONE LESIONS

    • cortical

      • Benign cortical defect

      • Avulsion cortical irregularity

    • medullary

      • Herniation pit

      • Nonossifying fibroma

      • Ossifying fibroma

      • Congenital generalized fibromatosis

    • corticomedullary

      • Nonossifying fibroma

      • Ossifying fibroma

      • Fibrous dysplasia

      • Cherubism

      • Desmoplastic fibroma

      • Fibromyxoma

  • MALIGNANT

    • Fibrosarcoma

Tumors of Histiocytic Origin

  • LOCALLY AGGRESSIVE

    • Giant cell tumor

    • Benign fibrous histiocytoma

  • MALIGNANT

    • Malignant fibrous histiocytoma

Tumors of Fatty Tissue Origin

  • BENIGN

    • Intraosseous lipoma

    • Parosteal lipoma

  • MALIGNANT

    • Intraosseous liposarcoma

  • Lipomas follow the signal intensity of subcutaneous fat in all sequences!

Tumors of Vascular Origin

<1% of all bone tumors

  • BENIGN

    • Hemangioma

    • Glomus tumor

    • Lymphangioma

    • Cystic angiomatosis

    • Hemangiopericytoma

  • MALIGNANT

    • Malignant hemangiopericytoma

    • Angiosarcoma = hemangioendothelioma

Metastatic sites: lung, brain, lymph nodes, other bones

Tumors of Neural Origin

  • BENIGN

    • Solitary neurofibroma

    • Neurilemoma

  • MALIGNANT

    • Neurogenic sarcoma = malignant schwannoma

Intraosseous lesion

Bubbly Bone Lesion

mnemonic: FOGMACHINES

  • Fibrous dysplasia, Fibrous cortical defect

  • Osteoblastoma

  • Giant cell tumor

  • Myeloma (plasmacytoma), Metastases from kidney, thyroid, breast

  • Aneurysmal bone cyst / Angioma

  • Chondromyxoid fibroma, Chondroblastoma

  • Histiocytosis X, Hyperparathyroid brown tumor, Hemophilia

  • Infection (Brodie abscess, Echinococcus, coccidioidomycosis)

  • Nonossifying fibroma

  • Enchondroma, Epithelial inclusion cyst

  • Simple unilocular bone cyst

Infectious Bubbly Lesion

  • Brodie abscess (Staph. aureus)

  • Coccidioidomycosis

  • Echinococcus

  • Atypical mycobacterium

  • Cystic tuberculosis

Blowout Lesion

  • METASTASES

    • Carcinoma of thyroid, kidney, breast

  • PRIMARY BONE TUMOR

    • Fibrosarcoma

    • Multiple myeloma (sometimes)

    • Aneurysmal bone cyst

    • Hemophilic pseudotumor

Nonexpansile Unilocular Well-demarcated Bone Defect

  • Fibrous cortical defect

  • Nonossifying fibroma

  • Simple unicameral bone cyst

  • Giant cell tumor

  • Brown tumor of HPT

  • Eosinophilic granuloma

  • Enchondroma

  • Epidermoid inclusion cyst

  • Posttraumatic / degenerative cyst

  • Pseudotumor of hemophilia

  • Intraosseous ganglion

    • P.9


  • Histiocytoma

  • Arthritic lesion

  • Endosteal pigmented villonodular synovitis

  • Fibrous dysplasia

  • Infectious lesion

Nonexpansile Multilocular Well-demarcated Bone Defect

  • Aneurysmal bone cyst

  • Giant cell tumor

  • Fibrous dysplasia

  • Simple bone cyst

Expansile Unilocular Well-demarcated Osteolysis

  • Simple unicameral bone cyst

  • Enchondroma

  • Aneurysmal bone cyst

  • Juxtacortical chondroma

  • Nonossifying fibroma

  • Eosinophilic granuloma

  • Brown tumor of HPT

Poorly Demarcated Osteolytic Lesion without Periosteal Reaction

  • NONEXPANSILE

    • Metastases from any primary neoplasm

    • Multiple myeloma

    • Hemangioma

  • EXPANSILE

    • Chondrosarcoma

    • Giant cell tumor

    • Metastasis from kidney / thyroid

Poorly Demarcated Osteolytic Lesion with Periosteal Reaction

  • Osteomyelitis

  • Ewing sarcoma

  • Osteosarcoma

Mixed Sclerotic and Lytic Lesion

Mixed Bone Lesion with Button Sequestrum

  • bone opacity surrounded by a well-defined lucent area

    common:

    • Osteomyelitis

    • Eosinophilic granuloma

    • Fibrosarcoma, desmoplastic fibroma, MFH

    • Lymphoma

  • uncommon:

    • partially calcified intraosseous lipoma, tuberculous osteitis, radiation necrosis, metastatic carcinoma, fibrous dysplasia, dermoid & epidermoid cyst, hemangioma, meningioma

Mixed Bone Lesion without Sequestrum

  • Osteomyelitis

  • Tuberculosis

  • Ewing sarcoma

  • Metastasis

  • Osteosarcoma

Trabeculated Bone Lesion

1. Giant cell tumor: delicate thin trabeculae
2. Chondromyxoid fibroma: coarse thick trabeculae
3. Nonossifying fibroma: lobulated
4. Aneurysmal bone cyst: delicate, horizontally oriented trabeculae
5. Hemangioma: striated radiating trabeculae

Lytic Bone Lesion Surrounded by Marked Sclerosis

mnemonic: BOOST

  • Brodie abscess

  • Osteoblastoma

  • Osteoid osteoma

  • Stress fracture

  • Tuberculosis

Multiple Lytic Lesions

mnemonic: FEEHMI

  • Fibrous dysplasia

  • Enchondromas

  • Eosinophilic granuloma

  • Hyperparathyroidism (brown tumors), Hemangiomas

  • Metastases, Multiple myeloma

  • Infection

Multiple Lytic Lesions in Child

  • Histiocytosis X

  • Metastatic neuroblastoma / leukemia

  • Fibrous dysplasia

  • Enchondromatosis

  • Rare: cystic angiomatosis, multifocal osteomyelitis

Lytic Bone Lesion in Patient <30 Years of Age

mnemonic: CAINES

  • Chondroblastoma

  • Aneurysmal bone cyst

  • Infection

  • Nonossifying fibroma

  • Eosinophilic granuloma

  • Solitary bone cyst

Lytic Bone Lesion on Both Sides of Joint

mnemonic: SAC

  • Synovioma

  • Angioma

  • Chondroid lesion

Multiple Bone Lesions & Soft-tissue Tumor

  • Neurofibromatosis & fibroxanthomas

  • Maffucci syndrome = enchondromatosis & hemangioma

  • Mazabraud syndrome = fibrous dysplasia & myxoma

  • Metastases

    • Multiple myeloma

    • Malignant melanoma

    • Lymphoma

Osteoblastic Bone Lesion

  • BENIGN

    • Bone island

    • Osteoma

    • Osteoid osteoma

    • P.10


  • MALIGNANT

    • Osteosarcoma

    • Parosteal sarcoma

Widespread Osteosclerotic Lesions

  • Metastases: prostate, breast, lung, bladder, pancreas, stomach, colon, carcinoid, brain

  • Paget disease

  • Sarcoma

  • Myelofibrosis

  • Mastocytosis

Dwarfism

Classification:

  • OSTEOCHONDRODYSPLASIA

    = abnormalities of cartilage / bone growth and development

    • identifiable at birth:

      • usually lethal: achondrogenesis, fibrochondrogenesis, thanatophoric dysplasia, short rib syndrome

      • usually nonlethal: chondrodysplasia punctata, camptomelic dysplasia, achondroplasia, diastrophic dysplasia, chondroectodermal dysplasia, Jeune syndrome, spondyloepiphyseal dysplasia congenita, mesomelic dysplasia, cleidocranial dysplasia, oto-palato-digital syndrome

    • identifiable in later life: hypochondroplasia, dyschondrosteosis, spondylometaphyseal dysplasia, acromicric dysplasia

    • abnormal bone density: osteopetrosis, pyknodysostosis, Melnick-Needles syndrome

  • DYSOSTOSIS

    = malformation of individual bones singly / in combination

    • with cranial + facial involvement:craniosynostosis, craniofacial dysostosis (Crouzon), acrocephalosyndactyly, acrocephalopolysyndactyly, branchial arch syndromes (Treacher-Collins, Franceschetti, acrofacial dysostosis, oculo-auriculo-vertebral dysostosis, hemifacial microsomia, oculo-mandibulo-facial syndrome

    • with predominant axial involvement:vertebral segmentation defects (Klippel-Feil), Sprengel anomaly, spondylocostal dysostosis, oculovertebral syndrome

    • with predominant involvement of extremities:acheiria (= absence of hands), apodia (= absence of feet), polydactyly, syndactyly, camptodactyly, Rubinstein-Taybi syndrome, pancytopenia-dysmelia syndrome (Fanconi), Blackfan-Diamond anemia with thumb anomaly, thrombocytopenia-radial aplasia syndrome, cardiomelic syndromes (Holt-Oram), focal femoral deficiency, multiple synostoses

  • IDIOPATHIC OSTEOLYSIS

    = disorders with multifocal resorption of bone

  • CHROMOSOMAL ABERRATION

  • PRIMARY METABOLIC DISORDER

    (a) calcium / phosphorus: hypophosphatasia
    (b) complex carbohydrates: mucopolysaccharidosis

Terminology:

Micromelia = shortening involves entire limb (eg, humerus, radius + ulna, hand)
Rhizomelia = shortening involves proximal segment (eg, humerus)
Mesomelia = shortening involves intermediate segment (eg, radius + ulna)
Acromelia = shortening involves distal segment (eg, hand)

Micromelic Dwarfism

= disproportionate shortening of entire leg

  • Mild micromelic dwarfism

    • Jeune syndrome

    • Ellis-van Creveld syndrome= chondroectodermal dysplasia

    • Diastrophic dwarfism

  • Mild bowed micromelic dwarfism

    • Camptomelic dysplasia

    • Osteogenesis imperfecta, type III

  • Severe micromelic dwarfism

    • Thanatophoric dysplasia

    • Osteogenesis imperfecta, type II

    • Homozygous achondroplasia

    • Hypophosphatasia

    • Short-rib polydactyly syndrome

    • Fibrochondrogenesis

Acromelic Dwarfism

= distal shortening (hands, feet)

  • Asphyxiating thoracic dysplasia

Rhizomelic Dwarfism

= shortening of proximal segments (humerus, femur)

mnemonic: MA CAT

  • Metatrophic dwarfism

  • Achondrogenesis (most severe shortening)

  • Chondrodysplasia punctata (autosomal recessive)

  • Achondroplasia, heterozygous

  • Thanatophoric dysplasia

Osteochondrodysplasia

  • Failure of

    • articular cartilage: spondyloepiphyseal dysplasia

    • ossification center: multiple epiphyseal dysplasia

    • proliferating cartilage: achondroplasia

    • spongiosa formation: hypophosphatasia

    • spongiosa absorption: osteopetrosis

    • periosteal bone: osteogenesis imperfecta

    • endosteal bone: idiopathic osteoporosis

  • Excess of

    • articular cartilage: dysplasia epiphysealis hemimelica

    • hypertrophic cartilage: enchondromatosis

    • spongiosa: multiple exostosis

    • periosteal bone: progressive diaphyseal dysplasia

    • endosteal bone: hyperphosphatemia

Lethal Bone Dysplasia

in order of frequency:

  • Thanatophoric dysplasia

  • Osteogenesis imperfecta type II

    • P.11


  • Achondrogenesis type I + II

  • Jeune syndrome (may be nonlethal)

  • Hypophosphatasia, congenital lethal form

  • Chondroectodermal dysplasia (usually nonlethal)

  • Chondrodysplasia punctata, rhizomelic type

  • Camptomelic dysplasia

  • Short-rib polydactyly syndrome

  • Homozygous achondroplasia

  • Lethal short-limbed dysplasias typically are manifest on sonograms before 24 weeks MA!

Nonlethal Dwarfism

  • Achondroplasia (heterozygous)

  • Asphyxiating thoracic dysplasia

  • Chondroectodermal dysplasia

  • Chondrodysplasia punctata

  • Spondyloepiphyseal dysplasia (congenital)

  • Diastrophic dwarfism

  • Metatrophic dwarfism

  • Hypochondroplasia

Late-onset Dwarfism

  • Spondyloepiphyseal dysplasia tarda

  • Multiple epiphyseal dysplasia

  • Pseudoachondroplasia

  • Metaphyseal chondrodysplasia

  • Dyschondrosteosis

  • Cleidocranial dysostosis

  • Progressive diaphyseal dysplasia

Hypomineralization in Fetus

  • DIFFUSE

    • Osteogenesis imperfecta

    • Hypophosphatasia

  • SPINE

    • Achondrogenesis

Large Head in Fetus

  • Achondroplasia

  • Thanatophoric dysplasia

Narrow Chest in Fetus

  • Short-rib polydactyly syndrome

  • Asphyxiating thoracic dysplasia

  • Chondroectodermal dysplasia

  • Camptomelic dysplasia

  • Thanatophoric dwarfism

  • Homozygous achondroplasia

  • Achondrogenesis

  • Hypophosphatasia

Platyspondyly

  • Thanatophoric dysplasia

  • Osteogenesis imperfecta type II

  • Achondroplasia

  • Morquio syndrome

Bowed Long Bones in Fetus

  • Camptomelic syndrome

  • Osteogenesis imperfecta

  • Thanatophoric dysplasia

  • Hypophosphatasia

Bone Fractures in Fetus

  • Osteogenesis imperfecta

  • Hypophosphatasia

  • Achondrogenesis

Limb reduction anomalies

Amelia = absence of limb
Hemimelia = absence of distal parts
Phocomelia = proximal reduction with distal parts attached to trunk

Aplasia / Hypoplasia of Radius

mnemonic: The Furry Cat Hit My Dog

  • Thrombocytopenia absent radius syndrome

  • Fanconi anemia

  • Cornelia de Lange syndrome

  • Holt-Oram syndrome

  • Myositis ossificans progressiva (thumb only)

  • Diastrophic dwarfism ( hitchhiker's thumb )

Pubic Bone Maldevelopment

mnemonic: CHIEF

  • Cleidocranial dysostosis

  • Hypospadia, epispadia

  • Idiopathic

  • Exstrophy of bladder

  • F for syringomyelia

Bone overgrowth

Bone Overdevelopment

  • Marfan syndrome

  • Klippel-Trenaunay syndrome

  • Nerve territory-oriented macrodactyly

    • Macrodystrophia lipomatosa

    • Fibrolipomatous hamartoma with macrodactyly

Erlenmeyer Flask Deformity

= expansion of distal end of long bones, usually femur

  • Gaucher disease, Niemann-Pick disease

  • Hemolytic anemia: thalassemia, sickle cell

  • Osteopetrosis

  • Heavy metal poisoning

  • Metaphyseal dysplasia = Pyle disease

  • Rickets

  • Fibrous dysplasia

  • Down syndrome

  • Achondroplasia

  • Rheumatoid arthritis

  • Hypophosphatasia

  • Leukemia

mnemonic: TOP DOG

  • Thalassemia

  • Osteopetrosis

  • Pyle disease

  • Diaphyseal aclasis

  • Ollier disease

  • Gaucher disease

P.12


Periosteal reaction / periostitis

1. Trauma, hemophilia  
2. Infection  
3. Inflammatory: arthritis
4. Neoplasm  
5. Congenital: physiologic in newborn
6. Metabolic: hypertrophic osteoarthropathy, thyroid acropachy, hypervitaminosis A
7. Vascular: venous stasis

Solid Periosteal Reaction

  • = reaction to periosteal irritant

  • even + uniform thickness >1 mm

  • persistent + unchanged for weeks

Patterns:

  • thin: eosinophilic granuloma, osteoid osteoma

  • dense undulating: vascular disease

  • thin undulating: pulmonary osteoarthropathy

  • dense elliptical: osteoid osteoma; long-standing malignant disease (with destruction)

  • cloaking: storage disease; chronic infection

Interrupted Periosteal Reaction

= pleomorphic, rapidly progressing process undergoing constant change

  • buttressing = periosteal bone formation merges with underlying cortex: eosinophilic granuloma

  • laminated = onion skin : acute osteomyelitis; malignant tumor (osteosarcoma, Ewing sarcoma)

  • radiating spicules = sunburst : osteosarcoma; Ewing sarcoma; chondrosarcoma; fibrosarcoma; leukemia; metastasis; acute osteomyelitis

  • perpendicular spicules = hair-on-end : Ewing sarcoma

  • amorphous: malignancy (deposits may represent extension of tumor / periosteal response); osteosarcoma

  • Codman triangle: hemorrhage; malignancy (osteosarcoma, Ewing sarcoma); acute osteomyelitis; fracture

Symmetric Periosteal Reaction in Adulthood

  • Venous stasis (lower extremity)

  • Hypertrophic osteoarthropathy

  • Pachydermoperiostosis

  • Thyroid acropachy

  • Fluorosis

  • Rheumatoid arthritis

  • Psoriatic arthritis

  • Reiter syndrome

  • Idiopathic-degenerative

Periosteal Reaction in Childhood

  • benign

    • Physiologic (up to 35%): symmetric involvement of diaphyses during first 1 6 months of life

    • Nonaccidental trauma = battered child syndrome

    • Infantile cortical hyperostosis: <6 months of age

    • Hypervitaminosis A

    • Scurvy

    • Osteogenesis imperfecta

    • Congenital syphilis

  • malignant

    • Multicentric osteosarcoma

    • Metastases from neuroblastoma + retinoblastoma

    • Acute leukemia

mnemonic: PERIOSTEAL SOCKS

  • Physiologic, Prostaglandin

  • Eosinophilic granuloma

  • Rickets

  • Infantile cortical hyperostosis

  • Osteomyelitis

  • Scurvy

  • Trauma

  • Ewing sarcoma

  • A-hypervitaminosis

  • Leukemia + neuroblastoma

  • Syphilis

  • Osteosarcoma

  • Child abuse

  • Kinky hair syndrome

  • Sickle cell disease

Periosteal Reaction in Infant

  • before 6 months of age

    • Infantile cortical hyperostosis

    • Physiologic

    • Extracorporeal membrane oxygenation

  • after 6 months of age

    • Hypervitaminosis A

    • Scurvy

    • Rickets

  • anytime during infancy

    • Nonaccidental trauma

    • Syphilis

    • Metastatic neuroblastoma / leukemia

    • Prostaglandin therapy: within 40 days

    • Sickle cell dactylitis

DDx: motion artifact

Enthesopathy

  • [en, Greek = in; thesis, Greek = position]

  • Enthesis = osseous attachment of tendon composed of 4 zones, ie, tendon itself + unmineralized fibrocartilage + mineralized fibrocartilage + bone

Cause:

  • Degenerative disorder

  • Seronegative arthropathies: ankylosing spondylitis, Reiter disease, psoriatic arthritis

  • Diffuse idiopathic skeletal hyperostosis

  • Acromegaly

  • Rheumatoid arthritis (occasionally)

Location: at site of tendon + ligament attachment

  • bone proliferation (enthesophyte)

  • calcification of tendon + ligament

  • erosion

Bone trauma

Childhood Fractures

  • Greenstick fracture

  • Bowing fracture

    • P.13


  • Traumatic epiphyseolysis

  • Battered child syndrome

  • Epiphyseal plate injury

Pseudarthrosis in Long Bones

  • Nonunion of fracture

  • Fibrous dysplasia

  • Neurofibromatosis

  • Osteogenesis imperfecta

  • Congenital: clavicular pseudarthrosis

Exuberant Callus Formation

  • Steroid therapy / Cushing syndrome

  • Neuropathic arthropathy

  • Osteogenesis imperfecta

  • Congenital insensitivity to pain

  • Paralysis

  • Renal osteodystrophy

  • Multiple myeloma

  • Battered child syndrome

Epiphysis

Premature Epiphyseal Ossification

  • @ Proximal femoral and humeral epiphyses

    • Jeune asphyxiating thoracic dysplasia

    • Ellis-van Creveld chondroectodermal dysplasia

Epiphyseal / Apophyseal Lesion

  • Chondroblastoma

  • Brodie abscess

  • Fungal / tuberculous infection

  • Langerhans cell histiocytosis

  • Osteoid osteoma

  • Chondromyxoid fibroma

  • Enchondroma

  • Bone cyst

  • Foreign-body granuloma

Subarticular Lesion

  • Giant cell tumor

  • Solitary subchondral cyst

  • Intraosseous ganglion

  • Brodie abscess

  • Clear cell chondrosarcoma

Stippled Epiphyses

  • Normal variant

  • Avascular necrosis

  • Hypothyroidism

  • Chondrodysplasia punctata

  • Multiple epiphyseal dysplasia

  • Spondyloepiphyseal dysplasia

  • Hypoparathyroidism

  • Down syndrome

  • Trisomy 18

  • Fetal warfarin syndrome

  • Homocystinuria (distal radial + ulnar epiphyses = pathognomonic)

  • Zellweger cerebrohepatorenal syndrome

Physeal / Metaphyseal Widening & Irregularity

  • Rickets

  • Hypophosphatasia

  • Metaphyseal chondroplasia

Epiphyseal Overgrowth

  • Juvenile rheumatoid arthritis

  • Hemophilia

  • Healed Legg-Perthes disease

  • Tuberculous arthritis

  • Pyogenic arthritis (chronic)

  • Fungal arthritis

  • Epiphyseal dysplasia hemimelica

  • Fibrous dysplasia of epiphysis

  • Winchester syndrome

Epiphyseolysis

= SLIPPED EPIPHYSIS(zone of maturing hypertrophic cartilage affected, not zone of proliferation)

  • Idiopathic / juvenile epiphyseolysis

    Age: 12 15 years (? puberty-related hormonal dysregulation)

    • adiposogenital type; tall stature

  • Renal osteodystrophy

  • Hyperparathyroidism in chronic renal disease

  • Hypothyroidism

  • Radiotherapy

Joints

Approach to Arthritis

mnemonic: ABCDE'S

  • Alignment

  • Bone mineralization

  • Cartilage loss

  • Distribution

  • Erosion

  • Soft tissues

Signs of Arthritis

Prevalence of arthritis: 15% of population in USA

Conventional x-ray:

  • narrowing of radiologic joint space:

    • uniform = inflammatory arthritis

    • nonuniform = degenerative arthritis

  • evidence of disease on both sides of joint:

    • osteopenia

    • subchondral sclerosis

    • erosion

    • subchondral cyst formation

    • malalignment

  • joint effusion

  • joint bodies

NUC:

  • increase in regional blood flow (active disease)

  • distribution of disease

MR:

  • irregularity + narrowing of articular cartilage

  • Gd-DTPA enhancement of synovium (active disease)

P.14


Classification of Arthritides

  • SEPTIC ARTHRITIS

    • Tuberculous

    • Pyogenic

    • Lyme arthritis

    • Fungal arthritis: Candida, Coccidioides immitis, Blastomyces dermatitidis, Histoplasma capsulatum, Sporothrix schenckii, Cryptococcus neoformans, Aspergillus fumigatus

      N.B.: Tuberculous + fungal arthritis shows prominent osteoporosis + slower rate of destruction + less joint narrowing than a pyogenic infection (Phemister triad)

  • COLLAGEN / COLLAGEN-LIKE DISEASE

    • Rheumatoid arthritis

    • Ankylosing spondylitis

    • Psoriatic arthritis

    • Rheumatic fever

    • Sarcoidosis

  • BIOCHEMICAL ARTHRITIS

    • Gout

    • Chondrocalcinosis

    • Ochronosis

    • Hemophilic arthritis

  • DEGENERATIVE JOINT DISEASE = Osteoarthritis

  • TRAUMATIC

    • Secondary osteoarthritis

    • Neurotrophic arthritis

    • Pigmented villonodular synovitis

  • ENTEROPATHIC ARTHROPATHY

    • INFLAMMATORY BOWEL DISEASE

      • Ulcerative colitis (in 10 20%)

      • Crohn disease (in 5%): peripheral arthritis increases with colonic disease

      • Whipple disease (in 60 90% transient intermittent polyarthritis: sacroiliitis, spondylitis)

        Resection of diseased bowel is associated with regression of arthritic symptomatology!

    • INFECTIOUS BOWEL DISEASE

      Infectious agents: Salmonella, Shigella, Yersinia

    • after intestinal bypass surgery

Spondyloarthritis and Positive HLA-B 27 Histocompatibility Complex

1. Ankylosing spondylitis 95%
2. Reiter disease 80%
3. Arthropathy of inflammatory bowel disease 75%
4. Psoriatic spondylitis 70%
5. Normal population 10%

Monoarthritis

Destructive Monoarthritis

  • Any destructive monoarthritis should be regarded as infection until proved otherwise!

  • Septic arthritis

  • Monoarticular presentation of a systemic arthritis

    • Rheumatoid arthritis

    • Gout

    • Amyloidosis

    • Seronegative arthritis

  • Joint tumor

    • PVNS

    • Synovial chondromatosis

    • Articular hemangioma

Nonseptic Monoarthritis

  • Gout

  • Milwaukee shoulder

  • Rapidly destructive articular disease

  • Amyloid arthropathy

  • Hemophilic arthropathy

  • Primary synovial osteochondromatosis

  • Pigmented villonodular synovitis

  • Neuropathic arthropathy

  • Foreign-body synovitis

Arthritis without Demineralization

  • Gout

  • Neuropathic arthropathy

  • Psoriasis

  • Reiter disease

  • Pigmented villonodular synovitis

mnemonic: PONGS

  • Psoriatic arthritis

  • Osteoarthritis

  • Neuropathic joint

  • Gout

  • Sarcoidosis

Arthritis with Demineralization

mnemonic: HORSE

  • Hemophilia

  • Osteomyelitis

  • Rheumatoid arthritis, Reiter disease

  • Scleroderma

  • Erythematosus, systemic lupus

Deforming Nonerosive Arthropathy

  • Collagen-vascular disease, especially SLE

  • Rheumatoid arthritis (rare)

  • Rheumatic fever (Jaccoud arthritis) (rare)

Arthritis with Periostitis

  • Juvenile rheumatoid arthritis

  • Psoriatic arthritis

  • Reiter syndrome

  • Infectious arthritis

Premature Osteoarthritis

mnemonic: COME CHAT

  • Calcium pyrophosphate dihydrate arthropathy

  • Ochronosis

  • Marfan syndrome

  • Epiphyseal dysplasia

  • Charcot joint = neuroarthropathy

  • Hemophilic arthropathy

  • Acromegaly

  • Trauma

Synovial Disease with Decreased Signal Intensity

= hemosiderin deposition

P.15


  • Pigmented villonodular synovitis

  • Rheumatoid arthritis

  • Hemophilia

Chondrocalcinosis

mnemonic: WHIP A DOG

  • Wilson disease

  • Hemochromatosis, Hemophilia, Hypothyroidism, 1 Hyperparathyroidism (15%), Hypophosphatasia, Familial Hypomagnesemia

  • Idiopathic (aging)

  • Pseudogout (CPPD)

  • Arthritis (rheumatoid, postinfectious, traumatic, degenerative), Amyloidosis, Acromegaly

  • Diabetes mellitus

  • Ochronosis

  • Gout

mnemonic: 3 C's
Crystals CPPD, sodium urate (gout)
Cations calcium (any cause of hypercalcemia), copper, iron
Cartilage degeneration osteoarthritis, acromegaly, ochronosis

Subchondral Cyst

  • = SYNOVIAL CYST = SUBARTICULAR PSEUDOCYST

  • = NECROTIC PSEUDOCYST = GEODES

    Etiology: bone necrosis allows pressure-induced intrusion of synovial fluid into subchondral bone; in conditions with synovial inflammation
    Cause: 1. Osteoarthritis
    2. Rheumatoid arthritis
    3. Osteonecrosis
    4. CPPD

  • size of cyst usually 2 35 mm

  • may be large + expansile (especially in CPPD)

    DDx: (1) Giant cell tumor
    (2) Pigmented villonodular synovitis
    (3)Metastasis
    (4) Intraosseous ganglion
    5) Hemophilia

Loose Intraarticular Bodies

  • Osteochondrosis dissecans

  • Synovial osteochondromatosis

  • Chip fracture from trauma

  • Severe degenerative joint disease

  • Neuropathic arthropathy

Intraarticular Process with Cortical Erosion

  • Pigmented villonodular synovitis

  • Synovial osteochondromatosis

  • Rheumatoid arthritis

  • Gout

  • Synovial hemangioma

  • Lipoma arborescens

Erosions of DIP Joints

  • Inflammatory osteoarthritis

  • Psoriatic arthritis

  • Gout

  • Multicentric reticulohistiocytosis

  • Hyperparathyroidism

  • Frostbite

  • Septic arthritis

Articular Disorders of Hand and Wrist

  • Osteoarthritis = degenerative joint disease

    • = abnormal stress with minor + major traumatic episodes

      Target areas: DIP, PIP, 1st CMC, trapezioscaphoid; bilateral symmetric / asymmetric

    • joint space narrowing

    • subchondral eburnation

    • marginal osteophytes + small ossicles

    • radial subluxation of 1st metacarpal base

    • Radiocarpal joint normal unless history of trauma

  • Erosive osteoarthritis = inflammatory osteoarthritis

    Age: predominantly middle-aged / postmenopausal women

    • acute inflammatory episodes

      Target areas: DIP, PIP, 1st CMC, trapezioscaphoid; bilateral symmetric / asymmetric

    • central erosions combined with osteophytes= subchondral gull wing erosions

    • joint space narrowing + sclerosis

    • rare ankylosis

  • Psoriatic arthritis

    • = rheumatoid variant / seronegative spondyloarthropathy; peripheral manifestation in monarthritis / asymmetric oligoarthritis / symmetric polyarthritis

      Target areas: all hand + wrist joints (commonly distal); bi- / unilateral asymmetric polyarticular changes

    • mouse ears marginal erosions

    • intraarticular osseous excrescences

    • new bone formation fusion

    • osteoporosis may be absent

  • Rheumatoid arthritis

    • = synovial proliferative granulation tissue = pannus

      Target areas: PIP (early in 3rd), MCP (earliest changes in 2nd + 3rd), all wrist joints (early in RC, IRU), ulnar styloid; both hands in relative symmetric fashion

    • fusiform soft-tissue swelling

    • regional periarticular osteoporosis

    • diffuse loss of joint space

    • marginal + central poorly defined erosions

    • joint deformities

  • Gouty arthritis

    • monosodium urate crystals in synovial fluid

    • asymptomatic periods from months to years

      Target areas: commonly CCMC + all hand joints

    • development of chronic tophaceous gout= lobulated soft-tissue masses

    • well-defined eccentric erosions with overhanging edge (often periarticular) + sclerotic margins

    • preservation of joint spaces

    • absence of osteoporosis

    • most extensive changes in common carpometacarpal compartment:

      P.16


      • scalloped erosions of bases of ulnar metacarpals

  • Calcium pyrophosphate dihydrate crystal deposition disease = CPPD

    Target areas: MCP (2nd, 3rd), radiocarpal; bilateral symmetric / asymmetric changes

    • chondrocalcinosis + periarticular calcifications:

      • calcification of triangular fibrocartilage

    • degenerative changes in unusual locations:

      • narrowing obliteration of space between distal radius and scaphoid fragmentation of surfaces

      • scapholunate separation

      • destruction of trapezioscaphoid space

    • no erosions

    • + large osteophytes = hemochromatosis

  • SLE

    • = myositis, symmetric polyarthritis, deforming nonerosive arthropathy, osteonecrosis

      Target areas: PIP, MCP

    • reversible deformities

  • Scleroderma = progressive systemic sclerosis (PSS)

    Target areas: DIP, PIP, 1st CMC

    • tuft resorption

    • soft-tissue calcifications

Arthritis Involving Distal Interphalangeal Joints

mnemonic: POEM

  • Psoriatic arthritis

    Articulations of Hand and Wrist

  • Osteoarthritis

  • Erosive osteoarthritis

  • Multicentric reticulohistiocytosis

Ankylosis of Interphalangeal Joints

mnemonic: S - Lesions

  • Psoriatic arthritis

  • Ankylosing spondylitis

  • Erosive osteoarthritis

  • Still disease

Sacroiliitis

Joint anatomy:

  • ligamentous portion (superior 2/3 to 1/2 of joint):

    formed by interosseous sacroiliac ligament

  • synovial component (inferior 1/3 to 1/2 of joint):

    the sacral surface is lined by 3 5 mm-thick hyaline cartilage; the iliac surface of joint is lined by 1 mm-thick fibrocartilage

  • 2 5 mm normal joint width

    Positioning: oblique view + modified Ferguson view = AP projection with 23 cephalad angulation

  • findings predominate on the iliac side (thinner cartilage)

  • BILATERAL SYMMETRIC

    • Ankylosing spondylitis

      • small regular erosion = loss of definition of white cortical line on iliac side (initially)

        Distribution Pattern of Arthritic Lesions (adapted from Donald Resnick, M.D.)

        • P.17


      • subchondral sclerosis + subsequent ankylosis

      • ossification of interosseous ligaments

    • Enteropathic arthropathy

      • same signs as in ankylosing spondylitis

    • Rheumatoid arthritis (in late stages)

      • joint space narrowing without reparation

      • osteoporosis

      • ankylosis may occur

    • Deposition arthropathy: gout, CPPD, ochronosis, acromegaly

      • slow loss of cartilage

      • subchondral reparative bone + osteophytes

    • Osteitis condensans ilii

    DDx: Hyperparathyroidism (subchondral bone resorption on iliac side resembling erosion + widening of joint)

  • BILATERAL ASYMMETRIC

    • Psoriatic arthritis

      • large extensive erosion

      • subchondral sclerosis + occasional ankylosis

    • Reiter syndrome

    • Juvenile rheumatoid arthritis

  • UNILATERAL

    • Infection

    • Osteoarthritis from abnormal mechanical stress

      • no erosions

      • irregular narrowing of joint space with subchondral sclerosis

      • osteophytes at anterosuperior / -inferior aspect of joint (may resemble ankylosis)

      DDx: psoriatic arthritis, Reiter syndrome, trauma, gout, pigmented villonodular synovitis, osteitis condensans ilii

Sacroiliac Joint Widening

mnemonic: CRAP TRAP

  • Colitis

  • Rheumatoid arthritis

  • Abscess (infection)

  • Parathyroid disease

  • Trauma

  • Reiter syndrome

  • Ankylosing spondylitis

  • Psoriasis

Sacroiliac Joint Fusion

mnemonic: CARPI

  • Colitic spondylitis

  • Ankylosing spondylitis

  • Reiter syndrome

  • Psoriatic arthritis

  • Infection (TB)

Widened Symphysis Pubis

mnemonic: EPOCH

  • Exstrophy of the bladder

  • Prune belly syndrome

  • Osteogenesis imperfecta

  • Cleidocranial dysostosis

  • Hypothyroidism

Arthritis of Interphalangeal Joint of Great Toe

  • Psoriatic arthritis

  • Reiter disease

  • Gout

  • Degenerative joint disease

Ribs

Thoracic Deformity

Funnel Chest = Pectus Excavatum

  • = posterior depression of sternum compressing heart against spine

  • Most frequently an isolated anomaly!

May be associated with:

  • prematurity, homocystinuria, Marfan syndrome, Noonan syndrome, fetal alcohol syndrome

    • depressed position of sternum (LATERAL)

    • indistinct right heart border mimicking right middle lobe process (FRONTAL)

    • decreased heart density (FRONTAL)

    • leftward displacement of heart mimicking cardiomegaly (FRONTAL)

    • horizontal course of posterior portion of ribs

    • accentuated downward course of anterior portions of ribs (FRONTAL)

Barrel Chest

  • = large sagittal diameter of thorax

    Cause: COPD, emphysema

  • lateral segments of ribs elongated + straight pointing vertical (FRONTAL)

  • square shape on cross section (CT)

Congenital Rib Anomalies

Prevalence: 1.4%

  • Cervical rib (0.2 1 8%)

    M<F

    • usually asymptomatic

    • thoracic outlet syndrome (due to elevation of floor of scalene triangle with decrease of costoclavicular space):

      Differential Diagnosis of Sacroiliac Joint Disease

        Osteoarthritis Ankylosing spondylitis ilii Osteitis condensans
      Age older younger younger
      Sex M, F M > F F > M
      Distribution bi- / unilateral symmetric bilateral symmetric bilateral
      Sclerosis iliac mild focal iliac extensive iliac triangular
      Erosions absent common absent
      Intraarticular ankylosis rare common absent
      Ligamentous ossification less common common absent

      P.18


      • 10 20% of symptomatic patients have a responsible cervical rib

      • 5 10% of complete cervical ribs cause symptoms

      May be associated with: Klippel-Feil anomaly

    • uni- / bilateral

    • may fuse with first ribs anteriorly

    • adjacent transverse process angulated inferiorly

      Cx: aneurysmal dilatation of subclavian a.
      DDx: elongated transverse process of 7th cervical vertebra; hypoplastic 1st thoracic rib

  • Forked / bifid rib (0.6%) = duplication of anterior portion

    Location: 4th rib (most often)
    May be associated with: Gorlin basal cell nevus syndrome

    • A single bifid rib is most commonly a normal incidental finding!

  • Rib fusion (0.3%)

    May be associated with: vertebral segmentation anomalies
    Location: 1st + 2nd rib / several adjacent ribs
    Site: posterior / anterior portion

  • Bone bridging = focal joining by bone outgrowth

    Cause: congenital / posttraumatic
    Location: anywhere along one pair of ribs / several adjacent ribs

    • complete bridging / pseudarthrosis

  • Rudimentary / hypoplastic rib (0.2%)

    Location: 1st rib (usually)

    • transverse process angulated superiorly

      DDx: cervical rib

  • Pseudarthrosis of 1st rib (0.1%)

    • radiolucent line through midportion with dense sclerotic borders

  • Intrathoracic / pelvic rib (rare)

  • Abnormal number of ribs

    • supernumerary: trisomy 21, VATER syndrome

    • 11 pairs: normal individuals (5 8%); trisomy 21 (33%); cleidocranial dysplasia; camptomelic dysplasia

Short Ribs

  • Thanatophoric dysplasia

  • Jeune asphyxiating thoracic dysplasia

  • Ellis-van Creveld chondroectodermal dysplasia

  • Short rib-polydactyly syndromes (Saldino-Noonan, Majewski, Verma-Naumoff)

  • Achondroplasia

  • Achondrogenesis

  • Mesomelic dwarfism

  • Spondyloepiphyseal dysplasia

  • Enchondromatosis

Rib Lesions

  • BENIGN RIB TUMOR

    • Fibrous dysplasia (most common benign lesion)

      • predominantly posterior location

    • Osteochondroma / exostosis: at costochondral / costovertebral junction

      Associated with: spontaneous hemothorax

    • Langerhans cell histiocytosis (eosinophilic granuloma)

    • Benign cortical defect

    • Hemangioma of bone

    • Enchondroma: at costochondral / costovertebral junction

    • Giant cell tumor

    • Aneurysmal bone cyst

    • Osteoblastoma

    • Osteoid osteoma

    • Chondroblastoma

    • Enostosis = bone island (0.4%)

    • Paget disease

    • Brown tumor of HPT

    • Xanthogranuloma

  • PRIMARY MALIGNANT RIB TUMOR

    • Chondrosarcoma (calcified matrix): most common

    • Plasmacytoma

    • Lymphoma

    • Osteosarcoma (rare)

    • Fibrosarcoma

    • Primitive neuroectodermal tumor (= Askin tumor)

  • SECONDARY MALIGNANT RIB TUMOR

    in adult: 1. Metastasis (most common malignant lesion)
    2. Multiple myeloma
    3. Desmoid tumor
    in child: 1. Ewing sarcoma (most common malignant tumor affecting ribs of children + adolescents)
    2. Metastatic neuroblastoma

  • TRAUMATIC RIB DISORDER

    • Healing fracture

    • Radiation osteitis

      DDx: pulmonary nodule

  • AGGRESSIVE GRANULOMATOUS INFECTIONS

    • = osteomyelitis

Expansile Rib Lesion

mnemonic: O FEEL THE CLAMP

  • Osteochondroma (25% of all benign rib tumors)

  • Fibrous dysplasia

  • Eosinophilic granuloma

  • Enchondroma (7% of all benign rib tumors)

  • Lymphoma / Leukemia

  • Tuberculosis

  • Hematopoiesis

  • Ewing sarcoma

  • Chondromyxoid fibroma

  • Lymphangiomatosis

  • Aneurysmal bone cyst

  • Metastases

  • Plasmacytoma

Abnormal Rib Shape

Rib Notching on Inferior Margin

  • = minimal concave scalloping / deep ridges along the neurovascular groove with reactive sclerosis

  • Minor undulations in the inferior ribs are normal!

  • The medial third of posterior ribs near transverse process of vertebrae may be notched normally!

    P.19


    • ARTERIAL

      Cause: intercostal aa. function as collaterals to descending aorta / lung

      • Aorta: coarctation (usually affects ribs 4 8; rare before age 8 years), thrombosis

      • Subclavian artery: Blalock-Taussig shunt

      • Pulmonary artery: pulmonary stenosis, tetralogy of Fallot, absent pulmonary artery

  • VENOUS

    Cause: enlargement of intercostal veins

    • AV malformation of chest wall

    • Superior vena cava obstruction

  • NEUROGENIC

    • Intercostal neuroma

    • Neurofibromatosis type 1

    • Poliomyelitis / quadriplegia / paraplegia

  • OSSEOUS

    • Hyperparathyroidism

    • Thalassemia

    • Melnick-Needles syndrome

Unilateral Rib Notching on Inferior Margin

  • Postoperative Blalock-Taussig shunt(subclavian to pulmonary artery)

  • Coarctation between origin of innominate a. + L subclavian a.

  • Coarctation proximal to aberrant subclavian a.

Rib Notching on Superior Margin

  • Rheumatoid arthritis

  • Scleroderma

  • Systemic lupus erythematosus

  • Hyperparathyroidism

  • Restrictive lung disease

  • Marfan syndrome

Dysplastic Twisted Ribbon Ribs

  • Osteogenesis imperfecta

  • Neurofibromatosis

Bulbous Enlargement of Costochondral Junction

  • Rachitic rosary

  • Scurvy

  • Achondroplasia

  • Hypophosphatasia

  • Metaphyseal chondrodysplasia

  • Acromegaly

Wide Ribs

  • Marrow hyperplasia (anemias)

  • Fibrous dysplasia

  • Paget disease

  • Achondroplasia

  • Mucopolysaccharidoses

Slender Ribs

  • Trisomy 18 syndrome

  • Neurofibromatosis

Dense Ribs

  • Tuberous sclerosis

  • Osteopetrosis

  • Mastocytosis

  • Fluorosis

  • Fibrous dysplasia

  • Chronic infection

  • Trauma

  • Subperiosteal rib resection

Hyperlucent Ribs

Congenitally Lucent Ribs

  • Osteogenesis imperfecta

  • Achondrogenesis

  • Hypophosphatasia

  • Camptomelic dysplasia

Acquired Lucent Ribs

  • Cushing disease

  • Acromegaly

  • Scurvy

Clavicle

Absence of Outer End of Clavicle

  • Rheumatoid arthritis

  • Hyperparathyroidism

  • Posttraumatic osteolysis

  • Metastasis / multiple myeloma

  • Cleidocranial dysplasia

  • Gorlin basal cell nevus syndrome

Penciled Distal End of Clavicle

mnemonic: SHIRT Pocket

  • Scleroderma

  • Hyperparathyroidism

  • Infection

  • Rheumatoid arthritis

  • Trauma

  • Progeria

Destruction of Medial End of Clavicle

mnemonic: MILERS

  • Metastases

  • Infection

  • Lymphoma

  • Eosinophilic granuloma

  • Rheumatoid arthritis

  • Sarcoma

Wrist & hand

Carpal Angle

= angle of 130 formed by tangents to proximal row of carpal bones

  • DECREASED CARPAL ANGLE (<124 )

    • Turner syndrome

    • Hurler syndrome

    • Morquio syndrome

    • Madelung deformity

  • INCREASED CARPAL ANGLE (>139 )

    • Down syndrome

    • Arthrogryposis

    • Bone dysplasia with epiphyseal involvement

P.20


Metacarpal Sign

  • = relative shortening of 4th + 5th metacarpals

  • tangential line along heads of 5th + 4th metacarpals intersects 3rd metacarpal

    • Idiopathic

    • Pseudo- and pseudopseudohypoparathyroidism

    • Basal cell nevus syndrome

    • Multiple epiphyseal dysplasia

    • Beckwith-Wiedemann syndrome

    • Sickle cell anemia

    • Juvenile chronic arthritis

    • Gonadal dysgenesis: Turner syndrome, Klinefelter syndrome

    • Ectodermal dysplasia = Cornelia de Lange syndrome

    • Hereditary multiple exostoses

    • Peripheral dysostosis

    • Melorheostosis

    mnemonic: Ping Pong Is Tough To Teach

    • Pseudohypoparathyroidism

    • Pseudopseudohypoparathyroidism

    • Idiopathic

    • Trauma

    • Turner syndrome

    • Trisomy 13 18

Lucent Lesion in Finger

  • BENIGN TUMOR

    • Enchondroma

    • Epidermoid inclusion cyst

    • Giant cell tumor

    • Reparative granuloma

    • Sarcoidosis

    • Glomus tumor (rare)

      others: aneurysmal bone cyst, brown tumor, hemophilic pseudotumor, solitary bone cyst, osteoblastoma

  • MALIGNANT TUMOR

    • Osteosarcoma

    • Fibrosarcoma

    • Metastasis from lung, breast, malignant melanoma

mnemonic: GAMES PAGES

  • Glomus tumor

  • Arthritis (gout, rheumatoid)

  • Metastasis (lung, breast)

  • Enchondroma

  • Simple cyst (inclusion)

  • Pancreatitis

  • Aneurysmal bone cyst

  • Giant cell tumor

  • Epidermoid

  • Sarcoid

Dactylitis

= expansion of bone with cystic changes

  • Tuberculous dactylitis (= spina ventosa)

  • Pyogenic / fungal infection

  • Syphilitic dactylitis

  • Sarcoidosis

  • Hemoglobinopathies

  • Hyperparathyroidism

  • Leukemia

Resorption of Terminal Tufts

  • TRAUMA

    • Amputation

    • Burns, electric injury

    • Frostbite

    • Vinyl chloride poisoning

  • NEUROPATHIC

    • Congenital indifference to pain

    • Syringomyelia

    • Myelomeningocele

    • Diabetes mellitus

    • Leprosy

  • COLLAGEN-VASCULAR DISEASE

    • Scleroderma

    • Dermatomyositis

    • Raynaud disease

  • METABOLIC

    • Hyperparathyroidism

  • INHERITED

    • Familial acroosteolysis

    • Pyknodysostosis

    • Progeria = Werner syndrome

    • Pachydermoperiostosis

  • OTHERS

    • Sarcoidosis

    • Psoriatic arthropathy

    • Epidermolysis bullosa

Acroosteolysis

  • Acroosteolysis: (a) acquired, (b) familial

  • Massive osteolysis

  • Essential osteolysis

  • Ainhum disease

Acquired Acroosteolysis

mnemonic: PETER's DIAPER SPLASH

  • Psoriasis, Porphyria

  • Ehlers-Danlos syndrome

  • Thrombangitis obliterans

  • Ergot therapy

  • Raynaud disease

  • Diabetes, Dermatomyositis, Dilantin therapy

  • Injury (thermal + electrical burns, frostbite)

  • Arteriosclerosis obliterans

  • PVC (polyvinylchloride) worker

  • Epidermolysis bullosa

  • Rheumatoid arthritis, Reiter syndrome

  • Scleroderma, Sarcoidosis

  • Progeria, Pyknodysostosis

  • Leprosy, Lesch-Nyhan syndrome

  • Absence of pain

  • Syringomyelia

  • Hyperparathyroidism

    also in: yaws; Kaposi sarcoma; pachydermoperiostosis

    • lytic destructive process involving distal + middle phalanges

    • NO periosteal reaction

    • epiphyses resist osteolysis until late

P.21


Acroosteosclerosis

= focal opaque areas + endosteal thickening

  • Incidental in middle-aged women

  • Rheumatoid arthritis

  • Sarcoidosis

  • Scleroderma

  • Systemic lupus erythematosus

  • Hodgkin disease

  • Hematologic disorders

Fingertip Calcifications

  • Scleroderma / CREST syndrome

  • Raynaud disease

  • Systemic lupus erythematosus

  • Dermatomyositis

  • Calcinosis circumscripta universalis

  • Hyperparathyroidism

Brachydactyly

= shortening / broadening of metacarpals phalanges

  • Idiopathic

  • Trauma

  • Osteomyelitis

  • Arthritis

  • Turner syndrome

  • Osteochondrodysplasia

  • Pseudohypoparathyroidism, Pseudopseudohypoparathyroidism

  • Mucopolysaccharidoses

  • Cornelia de Lange syndrome

  • Basal cell nevus syndrome

  • Hereditary multiple exostoses

Clinodactyly

= curvature of finger in mediolateral plane

  • Normal variant

  • Down syndrome

  • Multiple dysplasia

  • Trauma, arthritis, contractures

Polydactyly

  • Frequently associated with:

    • Carpenter syndrome

    • Ellis-van Creveld syndrome

    • Meckel-Gruber syndrome

    • Polysyndactyly syndrome

    • Short rib-polydactyly syndrome

    • Trisomy 13

Syndactyly

= osseous cutaneous fusion of digits

  • Apert syndrome

  • Carpenter syndrome

  • Down syndrome

  • Neurofibromatosis

  • Poland syndrome

  • Others

Shoulder

Shoulder Instability

= recurrent subluxation / dislocation of humeral head out of the glenoid socket during activities causing symptoms

Stabilizer: inferior glenohumeral ligament-labrum complex (most important); anterior labrum-ligament complex

Lesions after first anterior dislocation:

  • traumatic, unidrectional, Bankart, surgical (TUBS)

    Age: <40 years

    • fall on outstretched hand (FOOSH)

    • capsulolabral avulsion (Bankart lesion / its variant)

    • anterior-inferior instability

  • atraumatic, multidirectional, bilateral inferior (AMBRI)

    Age: >40 years

    • tear of supraspinatus tendon (33%)

    • fracture of greater tuberosity (33%)

    • subscapularis avulsion from humerus (33%)

Hip

Snapping Hip Syndrome

  • INTRAARTICULAR

    • Osteocartilaginous bodies

  • EXTRAARTICULAR = tendon slippage

    • fascia lata / gluteus maximus over greater trochanter

    • iliopsoas tendon over iliopectineal eminence

    • long head of biceps femoris over ischial tuberosity

    • iliofemoral ligament over anterior portion of hip capsule

Increase in Teardrop Width

  • increase in distance between teardrop + femoral head

    Cause: hip joint effusion

  • increase in mediolateral size of teardrop

    Cause: hip dysplasia, chronic hip joint effusion during skeletal maturation

Protrusio Acetabuli

  • = acetabular floor bulging into pelvis

  • medial wall of acetabulum projecting medially to ilioischial line by >3 mm (in males) / >6 mm (in females)

  • crossing of medial + lateral components of pelvic teardrop (U-shaped radiodense area medial to hip joint with

    • lateral aspect = acetabular articular surface

    • medial aspect = anteroinferior margin of quadrilateral surface of ilium)

  • UNILATERAL

    • Tuberculous arthritis

    • Trauma

    • Fibrous dysplasia

  • BILATERAL

    • Rheumatoid arthritis

    • Paget disease

    • Osteomalacia

P.22


mnemonic: PROT

  • Paget disease

  • Rheumatoid arthritis

  • Osteomalacia (HPT)

  • Trauma

Pain with Hip Prosthesis

Approximately 120,000 hip arthroplasties per year in USA

  • Heterotopic ossification

  • Trochanteric bursitis

  • Prosthetic fracture / periprosthetic fracture / cement fracture

  • Dislocation (due to capsular laxity / incorrect component placement)

  • Aseptic loosening

    Incidence: 50% of prostheses after 10 years/utable.

    Cause:

    • mechanical wear + tear

    • small-particle disease (= inflammatory-immune reaction to methylmethacrylate / metallic fragments activates phagocytes with secretion of cytokines + proteolytic enzymes leading to osteolysis)

      Rx: 30% require single-stage revision arthroplasty

  • Infection (= septic loosening)

    Incidence: 1 9%
    Organisms: Staphylococcus epidermidis (31%), Staphylococcus aureus (20%), Streptococcus viridans (11%), Escherichia coli (11%), Enterococcus faecalis (8%), group B streptococcus (5%)
    Time of onset: 33% within 3 months, 33% within 1 year, 33% >1 year after surgery
    Rx: excisional arthroplasty + protracted course of antimicrobial therapy + revision arthroplasty

Plain film:

  • migration of prosthetic components compared to previous film:

    • subsidence of prosthesis (up to 5 mm is normal for noncemented femoral component in first few months)

  • cement / prosthesis fracture

  • motion of components on stress views / fluoroscopy

  • widening of prosthesis-cement interface

  • lucency at cement-bone interface >2 mm

  • progressive widening of cement-bone lucency after 12 postoperative months

  • focal lytic area (due to particulate debris with foreign body granuloma / abscess)

  • extensive periostitis (in infection, but rare)

NUC (83% sensitive, 88% specific):

  • increased uptake of bone agent, Gallium-67, Indium-111 labeled leukocytes, complementary technetium-labeled sulfur colloid + combinations

Bone Scintigraphy:

  • normal = strong evidence against a prosthetic abnormality (= high NPV)

  • diffuse intense uptake around femoral component (= generalized osteolysis associated with aseptic loosening or infection)

  • focal uptake at distal tip of femoral component in >1 year old prosthesis = aseptic loosening

Sequential bone-gallium scintigraphy:

  • congruent spatial distribution of both tracers with gallium intensity less than bone tracer = no infection

  • spatially incongruent / intensity of gallium exceeds that of bone agent = infection

  • spatially congruent + similar intensity of both tracers = inconclusive

Combined labeled leukocyte marrow scintigraphy:

Accuracy: >90%
Concept: Tc-99m sulfur colloid maps aberrantly located normal bone marrow as a point of reference for leukocyte tracer

  • spatially congruent distribution of both radiotracers = no infection

  • labeled leukocyte activity without corresponding sulfur colloid activity = infection

Arthrography:

  • irregularity of joint pseudocapsule

  • filling of nonbursal spaces / sinus tracts / abscess cavities

Aspiration of fluid under fluoroscopy (12 93% sensitive, 83 92% specific for infection):

  • injection of contrast material to confirm intraarticular location

Evaluation of total hip arthroplasty

MEASUREMENTS

Reference line: transischial tuberosity line (R)

  • Leg length = vertical position of acetabular component = comparing level of greater / lesser tuberosity (T) with respect to line R

    High placement: shorter leg, less effective muscles crossing the hip joint
    Low placement: longer leg, muscles stretched to point of spasm with risk of dislocation

  • Vertical center of rotation

    = distance from center of femoral head (C) to line R

  • Horizontal center of rotation

    = distance from center of femoral head (C) to teardrop / other medial landmark

    Lateral position: iliopsoas tendon crosses medial to femoral head center of rotation increasing risk of dislocation

  • Lateral acetabular inclination = horizontal version

    • = angle of cup in reference to line R (40 10 desirable)

      Less angulation: stable hip, limited abduction
      Greater angulation:   risk of hip dislocation

    • Varus / neutral / valgus stem position

      Varus position: tip of stem rests against lateral endosteum, increased risk for loosening
      Valgus position: tip of stem rests against medial endosteum, not a significant problem

      P.23


      Initial Evaluation of Total Hip Arthroplasty

    • Acetabular anteversion (15 10 desirable)

      = lateral radiograph of groin

      Retroversion: risk of hip dislocation

    • Femoral neck anteversionworks synergistically with acetabular anteversion, true angle assessed by CT

Radiographic Findings in Total Hip Arthroplasty

  • NORMAL

    • irregular cement-bone interface

      • = normal interdigitation of PMMA (polymethyl-methacrylate) with adjacent bone remodeling providing a mechanical interlock

      • PMMA is not a glue!

    • thin lucent line along cement-bone interface

      • = 0.1 1.5-mm thin connective tissue membrane ( demarcation ) along cement-bone interface accompanied by thin line of bone sclerosis

  • ABNORMAL

    • wide lucent zone at cement-bone interface

      = 2-mm lucent line along bone-cement interface due to granulomatous membrane

      Cause: component loosening reaction to particulate debris (eg, PMMA, polyethylene)

    • lucent zone at metal-cement interface along proximal lateral aspect of femoral stem

      = suboptimal metal-cement contact at time of surgery / loosening

    • well-defined area of bone destruction(= histiocytic response, aggressive granulomatous disease)

      Cause: granulomatous reaction as response to particulate debris / infection / tumor

    • asymmetric positioning of femoral head within acetabular component

      Cause: acetabular wear / dislocation of femoral head / acetabular disruption / liner displacement / deformity

    • cement fracture

      Cause: loosening

Knee

Bone Contusion Pattern

  • edema of midportion of lateral femoral condyle

    Cause: pivot shift injury = valgus load + external rotation of tibia / external rotation of femurapplied to various states of flexion (noncontact injury)
    Predisposed: skier, football player

    Associated with injury of:

    • anterior cruciate lig. (midsubstance > femoral attachment > tibial attachment site)

    • posterior joint capsule + arcuate ligament

    • posterior horn of lateral / medial meniscus

    • medial collateral ligament

  • edema of posterior patellar surface

    Cause: dashboard injury = force upon anterior proximal tibia with knee in flexed position

    Associated with:

    • rupture of posterior cruciate lig. (midsubstance > femoral attachment > tibial attachment site)

    • tear of posterior joint capsule

    • fracture / osteochondral injury of patella

    • injury of hip

  • kissing bone contusion pattern = anterior aspect of tibial plateau + anterior aspect of femoral condyle

    Cause: hyperextension injury = direct force upon anterior tibia while foot is planted / indirect force of forceful kicking motion

    Associated with:

    • injury to posterior / anterior cruciate lig.

    • meniscal injury

    • dislocation of knee

    • popliteal neurovascular injury

    • complete disruption of posterolateral complex

    • P.24


  • edema in lateral aspect of femoral condyle (secondary to direct blow)

  • small area of edema in medial femoral condyle (due to avulsive stress to medial collateral ligament)

    Predisposed: football player
    Cause: clip injury = pure valgus stress with knee in mild flexion

    Associated with injury of:

    • medial collateral ligament (at femoral attachment site

    • anterior cruciate ligament

    • medial meniscus

    • combination of all three = O'Donoghue triad

  • anterolateral aspect of lateral femoral condyle

  • inferomedial aspect of patella

    Predisposed: teenaged / young adult athletes with shallow trochlear groove
    Cause: lateral patellar dislocation = twisting motionwith knee in flexion + quadriceps contraction

    Associated with injury of:

    • medial retinaculum

    • medial patellofemoral ligament (near femoral attachment site) most important stabilizing structure)

    • medial patellotibial ligament

Double PCL sign on MRI

  • Bucket-handle tear of medial / lateral meniscus

  • Ligament of Humphrey

  • Torn ACL

  • Fracture fragments

  • Osteophyte

  • Loose body

Absent bow-tie sign

  • Bucket-handle tear of medial meniscus

  • Congenitally hypoplastic / ring-shaped meniscus

  • Small meniscus in child / petite adult

  • Partial meniscectomy

  • Arthritic degeneration

Unique Tibial Lesions

  • Fibrous dysplasia

  • Ossifying fibroma

  • Adamantinoma

Tibiotalar Slanting

= downward slanting of medial tibial plafond

  • Hemophilia

  • Still disease

  • Sickle cell disease

  • Epiphyseal dysplasia

  • Trauma

Foot

Abnormal Foot Positions

  • FOREFOOT

    • Varus = adduction

      = axis of 1st metatarsal deviated medially relative to axis of talus

    • Valgus = abduction

      = axis of 1st metatarsal deviated laterally relative to axis of talus

    • Inversion = supination

      = inward turning of sole of foot

    • Eversion = pronation

      = outward turning of sole of foot

  • HINDFOOT

    talipes (talus, pes) = any deformity of the ankle and hindfoot

    • Equinus

      = hindfoot abnormality with reversal of calcaneal pitch so that the heel cannot touch the ground

    • Calcaneal foot

      = very high calcaneal pitch so that forefoot cannot touch the ground

    • Pes planus = flatfoot

      = low calcaneal pitch + (usually) heel valgus + forefoot eversion

    • Pes cavus

      = high calcaneal pitch (fixed high arch)

Clubfoot = Talipes Equinovarus

Common severe congenital deformity characterized by

  • equinus of heel (reversed calcaneal pitch)

  • heel varus (talocalcaneal angle of almost zero on AP view with both bones parallel to each other)

  • metatarsus adductus (axis of 1st metatarsal deviated medially relative to axis of talus)

  • Arthrogryposis multiplex congenita

  • Chondrodysplasia punctata

  • Neurofibromatosis

  • Spina bifida

  • Myelomeningocele

Rocker-bottom Foot = Vertical Talus

  • vertically oriented talus with increased talocalcaneal angle on lateral view

  • dorsal navicular dislocation at talonavicular joint

  • heel equinus

  • rigid deformity

Associated with: Arthrogryposis multiplex congenita; spina bifida; trisomy 13 18

Talar Beak = Hypertrophied Talar Ridge

  • Talocalcaneal type of tarsal coalition

  • Diffuse idiopathic skeletal hyperostosis (DISH)

  • Acromegaly

  • Rheumatoid arthritis

Heel Pad Thickening

= heel pad thickening >25 mm (normal <21 mm)

mnemonic: MAD COP

  • Myxedema

  • Acromegaly

  • Dilantin therapy

  • Callus

  • Obesity

  • Peripheral edema

P.25


Soft-tissue Masses of Foot + Ankle

  • NONTUMORAL

    • synovial proliferations

      • Pigmented villonodular synovitis (PVNS)

      • Giant cell tumor (GCT) of tendon sheath

    • posttraumatic

      • Plantar fasciitis

    • inflammatory

    • uncertain origin

      • Ganglion cyst

      • Epidermoid cyst

      • Morton neuroma

      • Florid reactive periostitis

      • Rheumatoid nodules

  • BENIGN TUMORS

    • Plantar fibromatosis

    • Deep fibromatosis

    • Infantile digital fibromatosis

    • Hemangioma

    • Nerve sheath tumor

    • Lipoma, angiolipoma

Soft tissues

Categories of Soft-tissue Masses

  • NEOPLASTIC

    Incidence: 300:100,000 annually; benign:malignant = 100:1

    • benign (most frequent)

      • Lipoma

      • Hemangioma

      • Desmoid tumor

      • Ganglion cyst

      • Pigmented villonodular synovitis

      • Neurofibroma (5%)

    • malignant (most frequent)

      Frequency: 1% of all cancers in adults, increasing with age

      • Malignant fibrous histiocytoma

      • Liposarcoma

  • INFLAMMATORY

  • TRAUMATIC

  • VASCULAR

Value of Conventional Radiographs

  • Identification of osseous abnormalities:callus related to fractures, osteocartilaginous mass, myositis ossificans

  • Identification of a primary bone lesion:osteomyelitis, Ewing sarcoma, osteosarcoma

Histologic Classification of Soft-tissue Lesions

  • FATTY

    • Lipoma

    • Angiolipoma

    • Liposarcoma

  • FIBROUS

    • Fibroma

    • Nodular fasciitis

    • Aggressive fibromatosis / desmoid

    • Fibrosarcoma

  • MUSCLE

    • Rhabdomyoma

    • Leiomyoma

    • Rhabdomyosarcoma

    • Leiomyosarcoma

  • VASCULAR

    • Hemangioma

    • Hemangiopericytoma

    • Hemangiosarcoma

  • LYMPH

    • Lymphangioma

    • Lymphangiosarcoma

    • Lymphadenopathy in lymphoma / metastasis

  • SYNOVIAL

    • Nodular synovitis

    • Pigmented villonodular synovitis

    • Synovial sarcoma

  • NEURAL

    • Neurofibroma

    • Neurilemoma

    • Ganglioneuroma

    • Malignant neuroblastoma

    • Neurofibrosarcoma

  • CARTILAGE AND BONE

    • Myositis ossificans

    • Extraskeletal osteoma

    • Extraskeletal chondroma

    • Extraskeletal chondrosarcoma

    • Extraskeletal osteosarcoma

Fat-containing Soft-tissue Masses

  • BENIGN LIPOMATOUS TUMORS

    • Lipoma

    • Intra- / intermuscular lipoma

    • Synovial lipoma

    • Lipoma arborescens = diffuse synovial lipoma

    • Neural fibrolipoma = fibrolipomatous tumor of nerve

    • Macrodystrophia lipomatosa

  • LIPOMA VARIANTS

    • Lipoblastoma (only in infancy + early childhood)

    • Lipomatosis = diffuse overgrowth of mature adipose tissue infiltrating through the soft tissues of affected extremity / trunk

    • Hibernoma = rare benign tumor of brown fat; often in peri- / interscapular region, axilla, thigh, chest wall

      • marked hypervascularity

  • MALIGNANT LIPOMATOUS TUMOR

    • Liposarcoma

  • OTHER FAT-CONTAINING TUMORS

    • Hemangioma

    • Elastofibroma

  • LESIONS MIMICKING FAT-CONTAINING TUMORS

    • Myxoid tumors: intramuscular myxoma, extraskeletal myxoid chondrosarcoma, myxoid malignant fibrous histiocytoma

    • Neural tumors: neurofibroma, neurilemoma, malignant schwannoma

      • 73% have tissue attenuation less than muscle

    • Hemorrhage

P.26


Extraskeletal Osseous + Cartilaginous Tumors

  • OSSEOUS SOFT-TISSUE TUMORS

    • cloudlike cumulus type of calcification

    • Myositis ossificans

    • Fibrodysplasia ossificans progressiva

    • Soft-tissue osteoma

    • Extraskeletal osteosarcoma

    • Myositis ossificans variants

      • Panniculitis ossificans

      • Fasciitis ossificans

      • Fibroosseous pseudotumor of digits

  • CARTILAGINOUS SOFT-TISSUE TUMORS

    • arcs and rings, spicules and floccules of calcification

    • Synovial osteochondromatosis

    • Soft-tissue chondroma

    • Extraskeletal chondrosarcoma

DDx:

  • Synovial sarcoma

  • Benign mesenchymoma

    = lipoma with chondroid / osseous metaplasia

  • Malignant mesenchymoma

    = 2 or more unrelated sarcomatous components

  • Calcified / ossified tophus of gout

  • Ossified soft-tissue masses of melorheostosis

  • Tumoral calcinosis

  • Pilomatricoma = calcifying epithelioma of Malherbe

    • lesion arises from hair matrix cells with slow growth confined to the subcutaneous tissue of the face, neck, upper extremities

    • central sandlike calcifications (84%)

    • peripheral ossification (20%)

Soft-tissue Calcification

Metastatic / Metabolic Calcification

= deposit of calcium salts in previously normal tissue

  • as a result of elevation of Ca P product above 60 70

  • with normal Ca P product after renal transplant

Location: lung (alveolar septa, bronchial wall, vessel wall), kidney, gastric mucosa, heart, peripheral vessels

Cause:

  • Skeletal deossification

    • 1 HPT

    • Ectopic HPT production (lung / kidney tumor)

    • Renal osteodystrophy + 2 HPT

    • Hypoparathyroidism

    • Prolonged immobilization

  • Massive bone destruction

    • Widespread bone metastases

    • Plasma cell myeloma

    • Leukemia

  • Hypercalcemia

    • Primary hyperparathyroidism

    • Hypervitaminosis D

    • Milk-alkali syndrome

    • Sarcoidosis

    • Hydroxyapatite deposition disease

    • IV administration of calcium salts

  • Idiopathic hypercalcemia

  • Hyperuricemia

    • Tophaceous gout

Dystrophic Calcification

= in presence of normal serum Ca + P levels secondary to local electrolyte / enzyme alterations in areas of tissue injury / inflammation

Cause:

  • Metabolic disorder without hypercalcemia

    • Renal osteodystrophy with 2 HPT

    • Hypoparathyroidism

    • Pseudohypoparathyroidism

    • Pseudopseudohypoparathyroidism

    • Gout

    • Pseudogout = chondrocalcinosis

    • Ochronosis = alkaptonuria

    • Diabetes mellitus

  • Connective tissue disorder

    • Scleroderma = progressive systemic sclerosis

    • Dermato- and polymyositis

    • Systemic lupus erythematosus

    • Mixed connective tissue disorders

  • Trauma

    • Neuropathic calcifications

    • Frostbite

    • Myositis ossificans progressiva

  • Infestation

    • Cysticercosis

    • Dracunculosis (guinea worm)

    • Loiasis

    • Bancroft filariasis

    • Hydatid disease

    • Leprosy

  • Vascular disease

    • Atherosclerosis

    • Media sclerosis (M nckeberg)

    • Venous calcifications

    • Tissue infarction (eg, myocardial infarction)

  • Miscellaneous

    • Ehlers-Danlos syndrome

    • Pseudoxanthoma elasticum

    • Werner syndrome = progeria

    • Calcinosis (circumscripta, universalis, tumoral calcinosis)

  • Neoplastic disease

    • Synovial sarcoma

    • Osteosarcoma

    • Chondrosarcoma

    • Necrotic tumor

  • Degenerative disease

    • Calcium pyrophosphate deposition disease

    • Calcific tendonitis (in 3% of adults)

      Location: shoulder > hip > elbow > wrist > knee

    • Calcific bursitis

  • Metaplasia

    • Synovial osteochondromatosis

Generalized Calcinosis

  • Collagen vascular disorders

    • Scleroderma

      • P.27


    • Dermatomyositis

  • Idiopathic calcinosis universalis

Idiopathic Calcification

  • Tumoral calcinosis

    • normal calcium + elevated phosphate levels

Interstitial Calcinosis

Calcinosis Circumscripta

  • firm white commonly ulcerating dermal papules / plaques / subcutaneous nodules extruding a chalky white material of hydroxyapatite

  • Acrosclerosis: granular deposits around joints of fingers + toes, fingertips

  • Scleroderma + CREST syndrome: acrosclerosis + absorption of ends of distal phalanges

  • Dermatomyositis: extensive subcutaneous deposits

  • Varicosities: particularly in calf

  • 1 Hyperparathyroidism: infrequently periarticular calcinosis

  • Renal osteodystrophy with 2 hyperparathyroidism: extensive vascular deposits even in young individuals

  • Hypoparathyroidism: occasionally around joints; symmetrical in basal ganglia

  • Vitamin D intoxication: periarticular in rheumatoid arthritis (puttylike); calcium deposit in tophi

Calcinosis Universalis

  • Progressive disease of unknown origin

    Age: children + young adults
    Associated with: poly- and dermatomyositis

  • plaque- / sheetlike calcium deposits in skin + subcutis; sometimes in tendons + muscles + fascia

  • NO true bone formation

Soft-tissue Ossification

= formation of trabecular bone

  • Myositis ossificans progressiva / circumscripta

  • Paraosteoarthropathy

  • Soft-tissue osteosarcoma

  • Parosteal osteosarcoma

  • Posttraumatic periostitis = periosteoma

  • Surgical scar

  • Severely burned patient

Connective Tissue Disease

  • = CTD = [COLLAGEN VASCULAR DISEASE]

  • = group of disorders that share a number of clinical + laboratory features

  • Features:

    • relatively specific: arthritis, myositis, Raynaud phenomenon with digital ulceration, tethered skin in extremities + trunk, malar rash sparing nasolabial folds, morning stiffness

    • relatively nonspecific: polyarthralgias (most common initial symptom), myalgias, mottling of extremities, muscle weakness + tenderness

  • Laboratory findings:

    • relatively specific: ANA in peripheral rim / nucleolar pattern, anti-DNA, elevated muscle enzyme

    • relatively nonspecific: ANA in homogeneous pattern, anti-single-stranded DNA, positive rheumatoid factor

Types and most distinctive features:

  • Rheumatoid arthritispositive rheumatoid factor, prominent morning stiffness, symmetric erosive arthritis

  • Systemic lupus erythematosusmalar rash, photosensitivity, serositis, renal disorders with hemolytic anemia, leukopenia, lymphopenia, thrombocytopenia, positive ANA

  • Sj gren syndromedry eyes + mouth, abnormal Schirmer test

  • SclerodermaRaynaud phenomenon, skin thickening of distal extremities proceeding to include proximal extremities + chest + abdomen, positive ANA in a nucleolar pattern

  • Polymyositis, dermatomyositisheliotrope rash over eyes, proximal muscle weakness, elevated muscle enzymes, inflammation at muscle biopsy

Mixed Connective Tissue Disease

  • = disorder that shares distinctive features of 2 different connective tissue diseases in same patient (eg, overlapping features of SLE, PSS, polymyositis)

  • pulmonary hypertension (due to interstitial pulmonary fibrosis / intimal proliferation of pulmonary arterioles)

Muscle

MR signal intensity of normal muscle:

  • higher than water + lower than fat on T1WI

  • much lower than water + fat on T2WI

Intramuscular Mass

  • NEOPLASM

  • INFECTION / INFLAMMATION

    • Intramuscular abscess

    • Focal myositis = benign inflammatory pseudotumor

    • Necrotizing fasciitis

    • Sarcoidosis

      • nodules with central star-shaped area of fibrosis surrounded by granuloma

  • MYONECROSIS

    • Sickle cell crisis

    • Poorly controlled diabetes

    • Compartment syndrome

    • Crush injury

    • Severe ischemia

    • Intraarterial chemotherapy

    • Rhabdomyolysis = severe muscle injury with loss of integrity of muscle cell membranes

      Cause: trauma, severe exercise, ischemia, burn, toxin, IV heparin therapy, autoimmune inflammation
      Cx: renal damage from myoglobulinemia, tetany, compartment syndrome

  • TRAUMA

    • Intramuscular hematoma (eg, severe muscle strain, laceration, contusion, spontaneous)

    • Myositis ossificans traumatica

P.28


Muscle Edema

muscle hyperintensity on STIR images

  • INFLAMMATION

    • Dermatomyositis

    • Polymyositis

    • Radiation therapy: straight sharp margins, involves muscle + subcutaneous fat

    • Early stage of myositis ossificans

  • CELLULAR INFILTRATE

    • Lymphoma

  • INFECTION

    • Bacterial / infectious myositis

      • direct extension from adjacent infection (eg, osteomyelitis, subcutaneous abscess)

      • hematogenous

    • Inclusion body myositis (probably due to para-myxovirus infection) resembling polymyositis

  • RHABDOMYOLYSIS

    • Sport / electric injury

    • Diabetic muscular infarction

    • Focal nodular myositis

    • Metabolic myopathy: eg, phosphofructokinase deficiency, hypokalemia, alcohol overdose

    • Viral myositis

  • TRAUMA

    • Subacute muscle denervation

      Time of onset: 2 4 weeks after denervation

      Mechanism:

      • spinal cord injury, poliomyelitis, peripheral nerve injury / compression (ganglion cyst, bone spur), Graves disease, neuritis

    • Muscle contusion (from direct blow)

    • Muscle strain (= injury at musculotendinous junction from overly forceful muscle contraction)

      Predilection for: hamstring, gastrocnemius m., biceps brachii m.)

    • Delayed-onset muscle soreness

      = overuse injury becoming symptomatic hours / days after overuse episode)

    • Compartment syndrome

      = increased pressure within indistensible space of confining fascia leading to venous occlusion, muscle + nerve ischemia, arterial occlusion, tissue necrosis

      Cause: trauma, burns, heavy exercise, extrinsic pressure, intramuscular hemorrhage

      • severe pain

      • dysfunction of sensory + motor nerves passing through affected compartment

    • Sickle cell crisis

Fatty Infiltration of Muscle

  • Chronic stage of muscle denervation (eg, poliomyelitis, stroke, peripheral nerve injury)

  • Chronic disuse (eg, chronic tendon tear, severe osteoarthritis)

  • Late stage of severe muscle injury

  • Long-term high-dose corticosteroid medication affecting truncal muscles

Fixation devices

Internal Fixation Devices

  • Screws

    • Cortical screw = shallow finely threaded over entire length, blunt tip

      Use: fixation of plates

    • Cancellous screw = wide thread diameter with varying length of smooth shank between head + threads

      Use: compression across fracture site

    • Malleolar screw = partially threaded

    • Interference screw = short, fully threaded, cancellous thread pattern, self-tapping tip, recessed head

      Use: within tunnel holding bone graft of ACL and PCL reconstruction

    • Cannulated screw = hollow screw inserted over guide pin

      Use: fracture of femoral neck

    • Herbert screw = cannulated screw threaded on both ends with different pitches, no screw head

      Use: scaphoid fracture

    • Dynamic hip screw = screw free to slide within barrel of side plate allowing impaction of fracture during healing without perforation of subarticular cortex

      Use: subcapital, intertrochanteric, subtrochanteric fracture

  • Washer

    • Flat washer = increase surface area over which force is distributed

    • Serrated washer = spiked edges used for affixing avulsed ligaments

  • Plates

    • compression plate

      Use: compression of stable fractures

    • neutralization plate = protects fracture from bending, rotation + axial-loading forces

    • buttress plate = support of unstable fractures in compression / axial loading

      • Straight plate

        • straight plate with round holes

        • dynamic compression plate = oval holes

        • tubular plate = thin pliable plate with concave inner surface

        • reconstruction plate = thin pliable plate to allow bending, twisting, contouring

      • Special plates

        T-shaped, L-shaped, Y-shaped, cloverleaf, spoon, cobra, condylar blade plate, dynamic compression screw system

  • Staples

    Fixation = bone = epiphyseal = fracture staples with smooth / barbed surface

    • Coventry = stepped osteotomy staple

    • stone = table staple

  • Wires

    • K wire = unthreaded segments of extruded wire of variable thickness

      Use: temporary fixation

    • Cerclage wiring = wire placed around bone

      P.29


      No Caption Available.

      P.30


      Use: fixation of comminuted patellar fracture, holding bone grafts in position

    • Tension band wiring = figure-of-eight wire placed on tension side of bone

      Use: olecranon / patellar fractures

External Fixation Devices

= smooth / threaded pins / wires attached to an external frame

  • unilateral pin = enters bone only from one side

    • Steinmann pin = large-caliber wire with pointed tip

    • Rush pin = smooth intramedullary pin

    • Schanz screw = pin threaded at one end to engage cortex, smooth at other end to connect to external fixation device

    • Knowles pin (for femoral neck fracture)

  • transfixing pin = passes through extremity supported by external fixation device on both ends

Intramedullary Fixation Devices

Use: diaphyseal long bone fractures

  • (a) nail = driven into bone without reaming

  • (b) rod = solid / hollow device with blunted tip driven into reamed channel (reaming disrupts blood supply and may decrease the rate of fracture healing)

  • (c) interlocking nail = accessory pins / screws / deployable fins placed to prevent rotation

  • 1. Rush pin = beveled end + hooked end

  • 2. Ender nail = oval in cross section

  • 3. Sampson rod = slightly curved rigid rod with fluted surface

  • 4. K ntscher nail = cloverleaf in cross section with rounded tip

P.31


Anatomy and Metabolism of Bone

Bone minerals

Calcium

  • 99% in bone

  • serum calcium

    • protein-bound fraction (albumin)

    • ionic (pH-dependent) 3% as calcium citrate / phosphate in serum

Absorption: facilitated by vitamin D
Excretion: related to dietary intake; >500 mg/24 hours = hypercalciuria

Phosphorus

Absorption: requires sodium; decreased by aluminum hydroxide gel in gut
Excretion: increased by estrogen, parathormone decreased by vitamin D, growth hormone, glucocorticoids

Bone marrow

  • Red marrow

    = hematopoietically active with a rich + extensive vascular supply, composed of erythrocyte + leukocyte + platelet precursors

    in adolescence: 40% fat, 40% water, 20% protein
    at age 70: 60% fat, 30% water, 10% protein

  • Yellow / fatty marrow

    with a sparse vascular network; composed of 80% fat, 15% water, 5% protein

    • Distribution changes throughout life with conversion from red to fatty marrow

      @ birth: marrow contains primarily hematopoietically active cells
      @ 1 year: phalanges of feet
      @ puberty: diaphysis of long bones
      @ 1st 2 decades: conversion begins in appendicular skeleton progressing to the axial skeleton; conversion in long bones begins in diaphysis > distal metaphysis > proximal metaphysis
      @ 3rd decade: residual red marrow remains in skull, spine, sternum, flat bones, proximal ends of humerus + femur; acetabulum superiorly + medially > ilium > around sacroiliac joints

Anatomic sites for MRI marrow screening:

  • spine (SAG images)

  • pelvis + femora (COR images)

    Parathormone Function

      PTH Action Net Effect
    Principal: (1) phosphate diuresis (1) Serum: increase in Ca
      (2) resorption of Ca + P from bone decrease in P
    Secondary: (3) resorption of Ca from gut (2) Urine: increase in Ca
      (4) reabsorption of Ca from renal tubule increase in P

  • Differences in signal intensity are maximized on T1WI but diminished on T2WI

  • red marrow:

    • iso- / slightly hyperintense compared with muscle on T1WI + T2WI (longer T1 relaxation time)

    • hypointense compared with fatty marrow (shorter T2 relaxation time)

  • yellow marrow:

    • isointense compared with subcutaneous fat on T1WI (relatively short T1 relaxation time compared with water)

    • iso- / hypointense compared with subcutaneous fat on T2WI

    • hyperintense compared with muscle on T2WI (long T2 relaxation time compared with water)

Hormones

Parathormone

Major stimulus: low levels of serum calcium ions (action requires vitamin D presence)

Target organs:

(a) BONE: increase in osteocytic + osteoclastic activity mobilizes calcium + phosphate = bone resorption
(b) KIDNEY: (1) increase in tubular reabsorption of Ca2+
(2) decrease in tubular reabsorption of phosphate (+ amino acids) = phosphate diuresis
(c) GUT: increased absorption of calcium + phosphorus

Major function:

  • increase of serum calcium levels

  • increase in serum alkaline phosphatase (50%)

Vitamin D Metabolism

required for

  • adequate calcium absorption from gut

  • synthesis of calcium-binding protein in intestinal mucosa

  • parathormone effects (stimulation of osteoclastic + osteocytic resorption of bone)

Biochemistry:

  • inactive form of vitamin D3 present through diet / exposure to sunlight (photoconversion of 7-dehydrocholesterol in skin to cholecalciferol); vitamin D3 is converted into 25-OH-vitamin D3 by liver and then converted into 1,25-OH vitamin D3 (biologically most active form = hormone) by kidney

    P.32


    Stimulus for conversion: (1) hypophosphatemia
    (2) PTH elevation

Action:

(a) BOWEL: (1) increased absorption of calcium from bowel
(2) increased absorption of phosphate from distal small bowel
(b) BONE: (1) proper mineralization of osteoid
(2) mobilization of calcium + phosphate (potentiates parathormone action)
(c) KIDNEY: (1) increased absorption of calcium from renal tubule
(2) increased absorption of phosphate from renal tubule
(d) CELL: binds to receptor on nucleus which leads to activation of genes involved in calcium homeostasis

Calcitonin

secreted by parafollicular cells of thyroid

Major stimulus: increase in serum calcium

Target organs:

(a) BONE: (1) inhibits parathormone-induced osteoclasis by reducing number of osteoclasts
(2) enhances deposition of calcium phosphate; responsible for sclerosis in renal osteodystrophy
(b) KIDNEY: inhibits phosphate reabsorption in renal tubule
(c) GUT: increases excretion of sodium + water into gut
Major function: decreases serum calcium + phosphate

Physis = Growth Plate

Four distinct zones of cartilage in longitudinal layers

  • Germinal zone = small cells

    adjacent to epiphyseal ossification center

  • Zone of proliferation = flattened cells

    arranged in columns

  • Zone of hypertrophy = swollen vacuolated cells

    • zone of maturation

    • zone of degeneration

    • zone of provisional calcification

  • Zone of primary and secondary spongiosa

Normal shoulder joint anatomy

Glenoid Labrum

  • = 4-mm wide fibrocartilaginous ring with considerable variation in shape attached to glenoid rim

  • variations in attachment above epiphyseal line (= junction of upper + middle thirds of glenoid body fossa)

  • labrum continuous with glenoid articular cartilage inferior to epiphyseal line

  • triangular / rounded shape on cross-sectional image

  • blends superiorly with biceps tendon

Superior Sublabral Sulcus / Recess

= variations in depth of sulcus between glenoid rim + labrum

Types of Attachment of the Biceps-Labral Complex

Location: 12 o'clock position at the site of biceps tendon attachment (in sagittal plane)

Types of attachment of biceps-labral complex (BLC):

  • BLC firmly adherent to superior pole of glenoid without a sulcus / sublabral foramen

  • small sulcus = BLC attached several mm medially; hyaline cartilage beneath labrum; may be continuous with sublabral foramen which is anterior to BLC

  • deep probe-patent sulcus = meniscoid labrum with large sulcus between labrum and hyaline cartilage

  • may be continuous with sublabral foramen

  • best visualized on coronal CT / MR

    DDx: type II SLAP lesion

Biceps Tendon

  • = long head of biceps muscle

  • attached to anterosuperior aspect of glenoid rim with fibers to

    • anterosuperior labrum (biceps-labral complex)

    • posterosuperior labrum (biceps-labral complex)

    • supraglenoid tubercle

    • base of coracoid process

  • exits joint through intertubercular groove

  • secured to intertubercular groove by transverse lig.

Glenohumeral Ligaments

= thickened bands of joint capsule functioning as shoulder stabilizers

Superior Glenohumeral Ligament

  • = most consistently identified

  • arises from upper pole of glenoid cavity and base of coracoid process

  • attaches to middle glenohumeral ligament + anterosuperior labrum + biceps tendon

  • inserts just superior to lesser tuberosity in region of bicipital groove

  • courses in plane perpendicular to middle glenohumeral ligament + parallel to coracoid process

  • best visualized on transverse CT / MR

Middle Glenohumeral Ligament (MGL)

  • = varies most in size + attachment; may be absent

  • ligament stretched when arm externally rotated

  • courses obliquely from superomedial to inferolateral

  • attaches medially on scapular neck / superior portion of anterior glenoid rim

  • attaches to anterior aspect of anatomic neck of humerus medial to lesser tuberosity

  • may be thick + cordlike

  • best visualized on sagittal / transverse CT / MR

    Normal Anatomy of Right Shoulder En Face (arrow in sublabral foramen)

P.33


Inferior Glenohumeral Ligament (IGL)

  • = important stabilizer of anterior shoulder joint, ie, it tightens during abduction + external rotation + prevents glenohumeral dislocation at the end range of motion

  • ligament + labrum function as single unit = glenohumeral labral-ligamentous complex

  • attaches to inferior 2/3 of the circumference of the entire labrum over a variable distance

  • attaches to humerus laterally

Parts:

  • Anterior band of IGL = thickened anterior-superior extent of ligament

  • Axillary pouch

  • Posterior band of IGL (usually thinner)

Normal Anatomic Variants of Shoulder

Sublabral Foramen = Sublabral Hole

= sublabral hole between labrum + glenoid

Incidence: 11% of individuals
Location: 2 o'clock position anterior to biceps tendon attachment

may coexist with sublabral recess

DDx: labral tear

Buford Complex

  • = cordlike thickening of middle glenohumeral ligament directly attaching to anterosuperior glenoid + absence of anterosuperior labrum

    Incidence: 1.5% of individuals
    Location: 2 o'clock position anterior to biceps tendon attachment

  • course of middle glenohumeral ligament can be followed on serial images from origin to insertion

  • may coexist with sublabral recess

    DDx: displaced anterosuperior labral fragment

    Buford Complex

    Rotator Cuff (dorsal aspect)

    Coracoacromial Arch (lateral aspect)

P.34


Foramen of Weitbrecht

= opening between SGL and MGL

Foramen of Rouviere

= opening between MGL and IGL

Rotator cuff muscles

mnemonic: SITS

  • Supraspinatus

  • Infraspinatus

  • Teres minor

  • Subscapularis

Occurrence of bone centers at elbow

mnemonic: CRITOE
Capitellum 1 year (3 6 months)
Radial head 4 years (3 6 years)
Internal humeral epicondyle 7 years (5 7 years, last to fuse)
Trochlea 10 years (9 10 years)
Olecranon 10 years (6 10 years)
External humeral epicondyle 11 years (9 13 years)
mnemonic: Nelson's X: 1, 7, 10, 11 years

Carpal bones

mnemonic: Some Lovers Try Positions That They Can't Handle
proximal row distal row
Scaphoid Trapezium
Lunate Trapezoid
Triquetrum Capitate
Pisiform Hamate

  • Remember that trapezium comes before trapezoid in the dictionary as well!

Ulnar Variance

  • = HULTEN VARIANCE = RADIOULNAR INDEX

  • = relative lengths of distal articular surfaces of radius and ulna

Definition:

  • neutral = both surfaces at same level = equal length of ulna + radius

  • positive = ulnar surface distal to radial surface = long ulna

  • negative = ulnar surface proximal to radial surface = short ulna

    Occurrence of Bone Centers (numbers in years)

    Carpal Tunnel (radiograph)

    Wrist Cross Section of Distal Radioulnar Joint with the 6 Extensor Compartments (dorsal aspect)

    Carpal Bones and Ligaments (volar aspect)

    P.35


    Central Segments of Scapholunate and Lunotriquetral Ligaments (coronal)

    Palmar and Dorsal Segments of Scapholunate and Lunotriquetral Ligaments (transverse)

Effect of wrist position:

  • increase of ulnar variance

    • maximum forearm pronation

    • firm grip

  • decrease of ulnar variance

    • maximum forearm supination

    • cessation of grip

Radiographic standard view of unloaded wrist:

  • posteroanterior, neutral forearm rotation, elbow flexed 90 , shoulder abducted 90

Lower extremity

Pes Anserinus

  • = [pes, Latin = foot; anser, Latin = goose]

  • = tendinous configuration of 3 flexors + medial rotators of knee joint attaching inferomedially to tibial tuberosity

    mnemonic: Say GraceSe before eating goose

    • Sartorius tendon (anterior)

    • Gracilis tendon (middle)

    • Semitendinosus tendon (posterior)

Iliotibial Tract

= strong stabilizing band of deep fascia composed of the fusion of aponeurotic coverings of:

  • Tensor fascia lata

  • Gluteus maximus m.

  • Gluteus medius m.

Insertion:

  • supracondylar tubercle of lateral femoral condyle

  • lateral tubercle of tibia = Gerdy tubercle (main site)

  • patella + patellar ligament

Hamstrings

  • medial hamstring

    • Semimembranosus m.

    • Semitendinosus m.

      Function: flexion + medial rotation of knee joint

  • lateral hamstring

    = long + short head of biceps femoris m.

    Function: flexion + lateral rotation of knee joint

Cruciate Ligaments

Both cruciate ligaments are intracapsular but extrasynovial!

Anterior Cruciate Ligament (ACL)

Function: limits anterior tibial translation
Origin: inner face of lateral femoral condyle
Insertion: noncartilaginous region of anterior aspect of intercondylar eminence of tibia
Anatomy: several distinct bundles of fibers
(1) large posterior bulk = spiraling together at femoral origin
(2) small anteromedial bundle diverging at tibial insertion

  • thin solid taut dark band (sagittal MR with knee in extension) almost parallel to intercondylar roof (= Blumensaat line):

    • with knee extension posterolateral band taut

    • with increasing flexion:

      anteromedial band becomes more taut + posterolateral band more lax

  • thin hypointense band parallel to inner aspect of lateral femoral condyle + fanlike configuration toward tibial spine (coronal MR)

  • thin ovoid hypointense band proximally, elliptical configuration distally with higher intensity (axial MR)

  • greater signal intensity than posterior cruciate ligament (due to anatomy)

Posterior Cruciate Ligament (PCL)

Function: limits posterior tibial translation
Origin: in a depression posterior to intercondylar region of tibia below joint surface
Insertion: most distal + anterior aspect of inner face of medial femoral condyle

  • thick dark band slightly posteriorly convex (arclike course on sagittal MR with knee in extension)

  • medial to ACL (coronal MR)

Collateral Ligaments of Knee Joint

Medial (Tibial) Collateral Ligament

Origin: just distal to adductor tubercle of femur
Insertion: anteromedial face of tibia distal to level of tibial tubercle about 5 cm below joint line

P.36


Muscle Attachments of Shoulder

Name of Muscle Origin Insertion
Deltoid lateral third of clavicle deltoid tuberosity of humerus
  lateral border of acromion deltoid tuberosity of humerus
  lower part of spinous process of scapula deltoid tuberosity of humerus
Subscapularis medial 2/3 of costal surface of scapula superior aspect of lesser tubercle of humerus
Pectoralis major    
    clavicular portion medial half of clavicle crest of greater tubercle of humerus
    sternocostal portion manubrium + corpus of sternum crest of greater tubercle of humerus
    abdominal portion anterior sheath of rectus abdominis crest of greater tubercle of humerus
Pectoralis minor 2nd / 3rd 5th ribs superomedial aspect of coracoid process
Biceps brachii    
    long head supraglenoid tubercle of scapula tuberosity of radius
    short head tip of coracoid process tuberosity of radius
Coracobrachialis tip of coracoid process medial surface of middle third of humerus
Supraspinatus supraspinatus fossa of scapula greater tubercle of humerus, highest facet
Infraspinatus infraspinatus fossa of scapula greater tubercle of humerus, middle facet
Teres minor upper 2/3 of lateral border of scapula greater tubercle of humerus, lower facet
Teres major dorsum of inferior angle of scapula inferior crest of lesser tubercle of humerus

Hip Flexors

Muscle Attachments of Thigh

Name of Muscle Origin Insertion
Gracilis inferior pubic ramus pes anserinus
Semimembranosus ischial tuberosity medial tibial condyle
Semitendinosus ischial tuberosity pes anserinus
Biceps femoris    
    long head ischial tuberosity fibular head
    short head lateral linea aspera fibular head
Adductor    
    longus superior pubic ramus medial linea aspera
    magnus inferior pubic ramus medial linea aspera
Sartorius anterior superior iliac spine pes anserinus
Quadriceps    
    rectus anterior inferior iliac spine patellar tendon
    vastus lateralis greater trochanter patellar tendon
    vastus medialis medial intertrochanteric line patellar tendon
Iliopsoas    
    iliacus ilium lesser trochanter
    psoas lumbar spine lesser trochanter
Tensor fasciae latae anterior superior iliac spine anterolateral tibia

P.37


Cross Section through L4-5

Cross Section through S1-2

Cross Section through Acetabular Roof

Cross Section through L5-S1

Cross Section through S4

Cross Section through Greater Trochanter

P.38


Cross Section through Obturator Foramen

Cross Section through Mid Thigh

Fat Pads of the Right Hip in Perfect AP Position

Cross Section through Minor Trochanter

Cross Section through Mid Thigh

Bony Landmarks of the Right Hip in Perfect AP Position

P.39


  • deep portion:

    • meniscofemoral ligament

    • meniscotibial ligaments

  • superficial portion

    • vertical band from femoral epicondyle to pes anserinus

    • posterior oblique ligament = posterior oblique band from femoral epicondyle to semimembranosus tendon

deep and superficial dark bands separated by a thin bursa + fatty tissue (on coronal MR)

Lateral (Fibular) Collateral Ligament

Origin: lateral aspect of lateral femoral condyle
Insertion: styloid process of fibular head

  • bicipital tendon + iliotibial band join lateral collateral ligament

Posterior Ankle Tendons

Achilles Tendon

Size: 7 mm in AP thickness (largest tendon of the body)
Origin: gastrocnemius + soleus muscle

  • surrounded by loose paratenon without tendon sheath

Plantaris Tendon

parallels Achilles tendon anteromedially

Insertion: Achilles tendon. calcaneus, plantar fascia

Medial Flexor Tendons

Posterior Tibialis Tendon

Size: twice the size of flexor digitorum longus tendon
Course: beneath medial malleolus (used as pulley)
Insertion: navicular, all cuneiforms, base of first four metatarsals, os naviculare

Flexor Digitorum Longus

 

Flexor Hallucis Longus

Course: groove beneath posterior process of talus, beneath sustentaculum tali
Insertion: base of distal phalanx of hallux

Cross Section through Distal Right Leg mnemonic for medial tendons: Tom, Dick and Harry from medial to lateral

  • Tibialis posterior

  • Digitorum longus (flexor)

  • Hallucis longus (flexor)

P.40


Plantar Compartments of the Midfoot

Plantar Compartments of the Forefoot

Medial compartment = bordered by medial septum (extending from plantar aponeurosis to navicular bone, medial cuneiform bone, and lateral border of plantar surface of 1st metatarsal bone); contains abductor hallucis m. + flexor hallucis brevis m. + flexor hallucis longus tendon
Lateral compartment = bordered by lateral septum (extending from plantar aponeurosis to medial surface of 5th metatarsal bone); contains abductor m. + short flexor m. + opponens m. of 5th toe
Central compartment = bordered by medial + lateral septa; communicates directly with posterior compartment of calf; subdivided by horizontal septa: adductor hallucis m. separated from quadratus plantae m.; contains flexor digitorum brevis m. + flexor digitorum longus tendon + quadratus plantae m. + lumbricales mm. + adductor hallucis m.
Deep subcompartment = bordered by transverse fascia of forefoot; separated from quadratus plantae m.; contains adductor hallucis m.

P.41


Accessory Ossicles of the Foot

  • Os talotibiale

  • Os supratalare

  • Os supranaviculare

  • Os infranaviculare

  • Os intercuneiforme

  • Os cuneometatarsale II dorsale

  • Os intermetatarsale

  • Secondary cuboid

  • Calcaneus secundarius

  • Os tibiale externum

  • Trigonum

  • Os accessorium supracalcaneum

  • Os subcalcis

  • Os peroneum

  • Os vesalianum

  • Talus accessorius

  • Os cuneonaviculare mediale

  • Sesamum tibiale anterius

  • Os cuneometatarsale I plantare

  • Cuboides secundarium

  • Os trochleare calcanei

  • Sesamoid talus - int. malleolus

  • Os subtibiale

  • Os sustentaculi

  • Os retinaculi

  • Os subfibulare

  • Talus secundarius

Calcaneal Pitch = Calcaneal Inclination Angle = determines longitudinal arch of foot; angle between line drawn along the inferior border of calcaneus connecting the anterior and posterior prominences + line representing the horizontal surface

Boehler Angle = angle between first line drawn from posterosuperior prominence of calcaneus anteriorly to sustentaculum tali + second line drawn from anterosuperior prominence posteriorly to sustentaculum tali; measures integrity of calcaneus

Talocalcaneal Angle on LAT View = angle between lines drawn through mid-transverse planes of talus + calcaneus; the midtalar line parallels the longitudinal axis of the first metatarsal

Intermetatarsal Angle = amount that 1st + 2nd metatarsals diverge from each other

Heel Valgus cannot be measured directly on radiographs but inferred from the talocalcaneal angle and estimated on coronal CT sections

Talocalcaneal Angle on AP View = KITE ANGLE = the midtalar and midcalcaneal lines parallel the 1st + 4th metatarsals; angle is greater in infants

Angle of Metatarsal Heads = obtuse angle formed by lines tangential to metatarsal heads

P.42


Bone and Soft-Tissue Disorders

Achondrogenesis

= autosomal recessive lethal chondrodystrophy characterized by extreme micromelia, short trunk, large cranium

TRIAD: (1) severe short-limb dwarfism
(2) lack of vertebral calcification
(3) large head with normal / decreased calvarial ossification
Birth prevalence: 2.3:100,000
Path: disorganization of cartilage

  • TYPE I = Parenti-Fraccaro disease

    • = defective enchondral + membranous ossification

    • complete lack of ossification of calvarium + spine + pelvis

    • absent sacrum + pubic bone

    • extremely short long bones without bowing, especially femur, radius, ulna

    • thin ribs with multiple fractures (frequent)

  • TYPE II = Langer-Saldino disease

    • = defective enchondral ossification only

    • good ossification of skull vault

    • nonossification of lower lumbar vertebrae + sacrum

    • short + stubby horizontal ribs without fractures

  • often subcutaneous edema

  • irregular flared metaphyses (esp. humerus)

  • short trunk with narrow chest + protruding abdomen

  • redundant soft tissues

  • polyhydramnios (common)

  • increase in HC:AC ratio

Prognosis: lethal often in utero / within few hours or days after birth (respiratory failure)
DDx: often confused with thanatophoric dwarfism

Achondroplasia

Heterozygous Achondroplasia

  • Prototype of rhizomelic dwarfism!

  • = autosomal dominant / sporadic (80%) disease with quantitatively defective endochondral bone formation; related to advanced paternal age; epiphyseal maturation + ossification unaffected

Incidence: 1:26,000 66,000 births, most common of lethal bone dysplasias; M < F

  • normal intelligence + motor function

  • neurologic defects

  • classically circus dwarfs

  • @ Skull

    • flat nasal bridge (hypoplastic base of skull)

    • macrocephaly + brachycephaly with enlarged bulging forehead (nonprogressive hydrocephalus)

    • relative prognathism

    • large calvarium with frontal bossing

    • depression of nasion

    • broad mandible

    • constricted basicranium + small foramen magnum:

      • communicating hydrocephalus caused by obstruction of basal cisterns + aqueduct

Cx: apnea + sudden death (due to compression of spinal cord + lower brain stem)

  • @ Chest

    • anteroposterior narrowing of chest

    • short anteriorly flared concave ribs

    • squaring of inferior scapular margin

  • @ Spine

    • hypoplastic bullet- / wedge-shaped vertebra:

      • rounded anterior beaking of vertebra in upper lumbar spine (DDx: Hurler disease)

      • decreased vertebral height

    • scalloped posteriorly concave vertebral margin

    • scoliosis:

      • thoracolumbar angular kyphosis (gibbus)

      • exaggerated sacral lordosis

    • stenosis of lumbar spine:

      • narrowing of interpedicular space due to laminar thickening

      • ventrodorsal narrowing of spine due to short pedicles

      • bulging / herniation of intervertebral disks

    • wide intervertebral foramina

  • @ Pelvis

    • protuberant abdomen

    • prominent buttocks

    • rolling gait from backward tilt of pelvis and hip joints

    • square flattened iliac bones = tombstone configuration

    • champagne glass -shaped pelvic inlet

    • lack of flaring of iliac wings

    • horizontal acetabula (= flat acetabular angle)

    • small sacrosciatic notch

  • @ Extremities

    • short stubby limbs + fingers

    • trident hand = separation of 2nd + 3rd digit and inability to approximate 3rd + 4th finger

    • limited range of motion of elbow

    • predominantly rhizomelic micromelia of long bones (femur, humerus):

      • trumpet appearance of long bones = shortening with disproportionate metaphyseal flaring (actually normal width of metaphysis)

      • short femoral necks

      • limb bowing

    • ball-in-socket epiphysis = broad V-shaped distal femoral metaphysis in which epiphysis is incorporated

    • high position of fibular head (= disproportionately long fibula)

    • short ulna with thick proximal + slender distal end

    • brachydactyly (short tubular bones of hand + feet), especially short proximal + middle phalanges

OB-US (diagnosable >21 27th week GA):

  • shortening of proximal long bones: femur length <99th percentile between 21 and 27 weeks MA

  • increased BPD, HC, HC:AC ratio

  • decreased FL:BPD ratio

  • normal mineralization, no fractures

  • normal thorax + normal cardiothoracic ratio

  • three-pronged (= trident) hand = 2nd + 3rd + 4th finger of similarly short length without completely approximating each other (= PATHOGNOMONIC)

P.43


Cx: (1) Hydrocephalus + syringomyelia (small foramen magnum)
(2) Recurrent ear infection (poorly developed facial bones)
(3) Neurologic complications (compression of spinal cord, lower brainstem, cauda equina, nerve roots): apnea and sudden death
4) Crowded dentition + malocclusion
Prognosis: long life
DDx: various mucopolysaccharidoses

Homozygous Achondroplasia

= hereditary autosomal dominant disease with severe features of achondroplasia (disproportionate limb shortening, more marked proximally than distally)

Risk: marriage of two achondroplasts to each other

  • large cranium with short base + small face

  • flattened nose bridge

  • short ribs with flared ends

  • hypoplastic vertebral bodies

  • decreased interpedicular distance

  • short squared innominate bones

  • flattened acetabular roof

  • small sciatic notch

  • short limb bones with flared metaphyses

  • short, broad, widely spaced tubular bones of hand

Prognosis: often stillborn; lethal in neonatal period (from respiratory failure)
DDx: thanatophoric dysplasia

Pseudoachondroplasia

= part of osteochondroplasias

Prevalence: 4:1,000,000
Etiology: mutation of genes encoding for cartilage oligomeric matrix protein (COMP) on chromosome 19 (closely related to multiple epiphyseal dysplasia)
Age at presentation: 2 4 years

  • normal facial features and intelligence

  • adult height 82 130 (mean, 118) cm

  • disturbance of gait

  • joint laxity

  • @ Skull: normal

  • @ Spine

    • persistent oval-shaped vertebral bodies

    • anterior beaking, platyspondyly

    • odontoid dysplasia

    • disk space widening

  • @ Extremities

    • short long bones with flared metaphyses

    • small irregular flared epiphyses with delayed development

    • medial beaking of proximal femoral neck (CHARACTERISTIC)

    • genu valgum, genu varum, genu recurvatum

    • shortening + widening of phalanges and metacarpals + metatarsals

  • @ Pelvis

    • widened triradiate cartilage

Cx: premature osteoarthritis
DDx: (1) Achondroplasia (large head with prominent frontal region + depressed bridge of nose, normal epiphyses, trident hands)
(2) Multiple epiphyseal dysplasia (near normal pelvis)
(3) Spondyloepiphyseal dysplasia congenita (hip joints more affected + near normal extremities)
(4) Diastrophic dwarfism (joint contractures and scoliosis at birth / in early infancy)
(5) Metatrophic dwarfism (dumbbell-shaped long bones + flattened vertebrae in infancy, less epiphyseal involvement)

Acrocephalosyndactyly

= syndrome characterized by

  • increased height of skull vault due to generalized craniosynostosis (= acrocephaly, oxycephaly)

  • syndactyly of fingers / toes

Type I : Apert syndrome = acrocephalosyndactyly
Type II : Vogt cephalosyndactyly
Type III : Acrocephalosyndactyly with asymmetry of skull + mild syndactyly
Type IV : Wardenburg type
Type V : Pfeiffer type

Acroosteolysis, Familial

dominant inheritance

Age: onset in 2nd decade; M:F = 3:1

  • sensory changes in hands + feet

  • destruction of nails

  • joint hypermobility

  • swelling of plantar of foot with deep wide ulcer + ejection of bone fragments

  • @ Skull

    • wormian bones

    • craniosynostosis

    • basilar impression

    • protuberant occiput

    • resorption of alveolar processes + loss of teeth

  • @ Spine

    • spinal osteoporosis fracture

    • kyphoscoliosis + progressive decrease in height

Acromegaly

Etiology: excess growth hormone due to eosinophilic adenoma / hyperplasia in anterior pituitary

  • gigantism in children: advanced bone age + excessive height (DDx: Soto syndrome of cerebral gigantism = large skull, mental retardation, cerebral atrophy, advanced bone age)

  • osseous enlargement (phalangeal tufts, vertebrae)

  • flared ends of long bone

  • cystic changes in carpals, femoral trochanters

  • osteoporosis

  • @ Hand

    • spadelike hand

    • widening of terminal tufts

  • @ Skull

    • prognathism (= elongation of mandible) in few cases

    • sellar enlargement + erosion

    • enlargement of paranasal sinuses: large frontal sinuses (75%)

      • P.44


    • calvarial hyperostosis (especially inner table)

    • enlarged occipital protuberance

  • @ Vertebrae

    • posterior scalloping in 30% (secondary to pressure of enlarged soft tissue)

    • anterior new bone

    • loss of disk space (weakening of cartilage)

  • @ Soft tissue

    • heel pad >25 mm

  • @ Joints

    • premature osteoarthritis (commonly knees)

Actinomycosis

= chronic suppurative infection characterized by formation of multiple abscesses, draining sinuses, abundant granulation tissue secondary to mucosal disruption + low tissue oxygen tension

Organism: Actinomyces israelii / naeslundii / viscosus / eriksonii, gram-positive non acid-fast anaerobic pleomorphic small filamentous bacterium with proteolytic activity, superficially resembling the morphology of a hyphal fungus (Gomori methenamine silver stain-positive filaments); closely related to mycobacteria

Spread:

  • contiguous: production of proteolytic enzymes allows crossing of normal anatomic barriers

  • hematogenous

Histo: mycelial form in tissue; as opportunistic pathogens rod-shaped bacterial form normally inhabits oropharynx (dental caries, gingival margins, tonsillar crypts) + GI tract
Predisposed: individuals with very poor dental hygiene, immunosuppressed patients
Location: mandibulofacial > intestinal > lung

Clinical types:

  • Mandibulo- / cervicofacial actinomycosis (55%)

    Cause: poor oral hygiene

    • draining cutaneous sinuses

    • sulfur granules in sputum / exudate = colonies of organisms arranged in circular fashion = mycelial clumps with thin hyphae 1 2 mm in diameter

    • osteomyelitis of mandible (most frequent bone involved) with destruction of mandible around tooth socket

    • no new-bone formation

    • spread to soft tissues at angle of jaw + into neck

  • Abdominopelvic / ileocecal / abdominal actinomycosis (20%)

    Cause: rupture / surgery of appendix; IUD use (25% of IUDs become eventually colonized with serious infections in 2 4%)
    Location: initially localized to cecum / appendix

    • fever, leukocytosis, mild anemia

    • weight loss, nausea, vomiting

    • lower abdominal pain

    • chronic sinus in groin, vaginal discharge

    • yellow / brown sulfur granules on cervical Papanicolaou smear

    • fold thickening + ulcerations (resembling Crohn disease)

    • rupture of abdominal viscus (usually appendix)

    • fistula formation

    • abscess in liver (15%), retroperitoneum, psoas muscle, pelvis, tubo-ovarian abscess (containing yellow sulfur granules = 1 2-mm colony of gram-positive bacilli)

    • hydronephrosis (due to ureteral compression by pelvic abscess)

  • Pleuropulmonary / thoracic actinomycosis (15%)

    Cause: aspiration of infected material from oropharynx / hematogenous spread
    Predisposed: alcoholics
    Histo: masses of PMN leukocytes containing round actinomycotic / sulfur granules surrounded by a rim of granulation tissue

    • @ Lung

      • draining chest wall sinuses (spread through fascial planes)

      • enhancing extensive transfissural chronic segmental consolidation (acute airspace pneumonia rare); usually unilateral + upper lobe predominance

      • cavitary lesion (abscess) with ringlike enhancement

      • fibrotic pleuritis

      • chronic pleural effusion / empyema

        CT:

        • central areas of low attenuation within consolidation

        • adjacent pleural thickening

        DDx: carcinoma, tuberculosis, bacterial / fungal pneumonia

    • @ Vertebra + ribs

      • destruction of vertebra with preservation of disk + small paravertebral abscess without calcification (DDx to tuberculosis: disk destroyed, large abscess with calcium)

      • thickening of cervical vertebrae around margins

      • destruction / thickening of ribs

  • Mixed organs (10%)

    • @ Tubular bones of hands

      • destructive lesion of mottled permeating type

      • cartilage destruction + subarticular erosive defects in joints (simulating TB)

    • @ Skin, brain, pericardium

Dx: anaerobic culture; species-specific antibodies
Rx: surgical d bridement + high doses of penicillin

Adamantinoma

  • = (MALIGNANT) ANGIOBLASTOMA

  • = locally aggressive / malignant lesion

    Histo: pseudoepithelial cell masses with peripheral columnar cells in a palisade pattern with varying amounts of fibrous stroma; areas of squamous / tubular / alveolar / vessel transformation; prominent vascularity; resembles ameloblastoma of the jaw
    Age: 25 50 years, commonest in 3rd 4th decade

  • frequently history of trauma

  • local swelling pain

    Location: middle 1/3 of tibia (90%), fibula, ulna, carpals, metacarpals, humerus, shaft of femur

  • eccentric round osteolytic lesion with sclerotic margin, may have additional foci in continuity with major lesion (CHARACTERISTIC)

    • P.45


  • may show mottled density

  • bone expansion frequent

  • often multiple

    Prognosis: tendency to recur after local excision; after several recurrences pulmonary metastases may develop
    DDx: fibrous dysplasia (possibly related)

Ainhum Disease

  • = DACTYLOLYSIS SPONTANEA

  • [ainhum, Brazilian tribal language = fissure, saw, sword]

    Etiology: unknown
    Histo: hyperkeratotic epidermis with fibrotic thickening of collagen bundles below; chronic lymphocytic inflammatory reaction may be present; arterial walls may be thickened with narrowed vessel lumina
    Incidence: up to 2%
    Age: usually in males in 4th + 5th decades; Blacks (West Africa) + their American descendants; M > F

  • deep soft-tissue groove forming on medial aspect of plantar surface of proximal phalanx with edema distally

  • painful ulceration may develop

    Location: mostly 5th / 4th toe (rarely finger); near interphalangeal joint; mostly bilateral

  • sharply demarcated progressive bone resorption of distal / middle phalanx with tapering of proximal phalanx to complete autoamputation (after an average of 5 years)

  • osteoporosis

Rx: early surgical resection of groove with Z-plasty
DDx: (1) Neuropathic disorders (diabetes, leprosy, syphilis)
(2) Trauma (burns, frostbite)
(3) Acroosteolysis from inflammatory arthritis, infection, polyvinyl chloride exposure
(4) Congenitally constricting bands in amniotic band syndrome

Amyloidosis

= extracellular deposition of a chemically diverse group of protein polysaccharides in body tissues ( 2-microglobulin); tends to form around capillaries + endothelial cells of larger blood vessels causing ultimately vascular obliteration with infarction

2-microglobulin = low-molecular-weight serum protein not filtered by standard dialysis membranes

Path: stains with Congo red
At risk: patients on long-term hemodialysis

  • bone pain (eg, shoulder pain)

  • periarticular rubbery soft-tissue swelling + stiffness (shoulders, hips, fingers):

    • carpal-tunnel syndrome (commonly bilateral)

  • Bence Jones protein (without myeloma)

Amyloid Arthropathy

= synovial-articular pattern of amyloidosis

Location: cervical spine, hip, shoulder, elbow

  • juxtaarticular soft-tissue swelling (amyloid deposited in synovium, joint capsule, tendons, ligaments) extrinsic osseous erosion

  • mild periarticular osteoporosis

  • subchondral cysts + well-defined sclerotic margin

  • joint space preserved until late in course of disease

  • subluxation of proximal humerus + femoral neck

  • MR:

    • extensive deposition of abnormal soft tissue of low to intermediate signal intensity on T1WI + T2WI covering synovial membrane, filling subchondral defects, extending into periarticular tissue

    • joint effusion

DDx: inflammatory arthritis

Diffuse Amyloid Marrow Deposition

  • generalized osteoporosis

  • coarse trabecular pattern (DDx: sarcoidosis)

  • pathologic collapse of vertebral body may occur

Amyloidoma

  • = localized destructive lesion of amyloidosis (rarest form)

    Location: appendicular > axial skeleton

  • focal medullary lytic lesion with endosteal scalloping ( secondary invasion + erosion of articular bone)

    Cx: pathologic fracture

Aneurysmal Bone Cyst

= expansile pathologically benign lytic lesion of bone containing thin-walled cystic cavities filled with chronic blood products; name derived from roentgen appearance

Etiology:

  • primary ABC (65 99%)

    local circulatory disturbance as a result of trauma

  • secondary ABC (1 35%)

    arising in preexisting bone tumor causing venous obstruction / arteriovenous fistula: giant cell tumor (39%), osteoblastoma, chondroblastoma, angioma, telangiectatic osteosarcoma, solitary bone cyst, fibrous dysplasia, xanthoma, chondromyxoid fibroma, nonossifying fibroma, metastatic carcinoma

Histo: intraosseous arteriovenous malformation with honeycombed spaces filled with blood + lined by granulation tissue / osteoid; areas of free hemorrhage; sometimes multinucleated giant cells; solid component predominates in 5 7%

Types:

  • INTRAOSSEOUS ABC

    • = primary cystic / telangiectatic tumor of giant cell family, originating in bone marrow cavity, slow expansion of cortex; rarely related to history of trauma

  • EXTRAOSSEOUS ABC

    • = posttraumatic hemorrhagic cyst; originating on surface of bones, erosion through cortex into marrow

Age: peak age 16 years (range 10 30 years); in 75% <20 years; F > M

  • pain of relatively acute onset with rapid increase of severity over 6 12 weeks

  • history of trauma

  • neurologic signs (radiculopathy to quadriplegia) if in spine

Location: (a) spine (12 30%) with slight predilection for posterior elements; thoracic > lumbar > cervical spine (22%); involvement of vertebral body (40 90%); may involve two contiguous vertebrae (25%)
(b) long bones: eccentric in metaphysis of femur, tibia, humerus, fibula; pelvis

P.46


  • purely lytic eccentric radiolucency

  • aggressive expansile ballooning lesion of soap-bubble pattern + thin internal trabeculations

  • rapid progression within 6 weeks to 3 months

  • sclerotic inner portion

  • almost invisible thin cortex (CT shows integrity)

  • tumor respects epiphyseal plate

  • no periosteal reaction (except when fractured)

CT:

  • blood-filled sponge = fluid-fluid / hematocrit levels due to blood sedimentation (in 10 35%)

MR:

  • multiple cysts of different signal intensity representing different stages of blood by-products:

    • heterogeneous fluid-fluid levels within loculations reflecting hemorrhage with sedimentation

    low-signal intensity rim = intact thickened periosteal membrane

  • heterogeneous enhancement

NUC:

  • doughnut sign = peripheral increased uptake (64%)

Angio:

  • hypervascularity in lesion periphery (in 75%)

Prognosis: 20 30% recurrence rate
Rx: preoperative embolotherapy; complete resection; radiation therapy (subsequent sarcoma possible)
Cx: (1) pathologic fracture (frequent)
(2) extradural block with paraplegia
DDx: (1) Giant cell tumor (particularly in spine)
(2) Hemorrhagic cyst (end of bone / epiphysis, not expansile)
(3) Enchondroma
(4) Metastasis (renal cell + thyroid carcinoma)
(5) Plasmacytoma
(6) Chondro- and fibrosarcoma
(7) Fibrous dysplasia
(8) Hemophilic pseudotumor
(9) Hydatid cyst

Angiomatosis

= diffuse infiltration of bone / soft tissue by hemangiomatous / lymphangiomatous lesions

Age: first 3 decades of life

May be associated with:

  • chylothorax, chyloperitoneum, lymphedema, hepatosplenomegaly, cystic hygroma

  • OSSEOUS ANGIOMATOSIS (30 40%)

    • indolent course

      Location: femur > ribs > spine > pelvis > humerus > scapula > other long bones > clavicle

    • osteolysis with honeycomb / latticework ( hole-within-hole ) appearance

    • may occur on both sides of joint

      DDx: solitary osseous hemangioma

  • CYSTIC ANGIOMATOSIS

    • = extensive involvement of bone

      Histo: endothelium-lined cysts in bone
      Age: peak 10 15 years; range of 3 months to 55 years
      Location: long bones, skull, flat bones

    • multiple osteolytic metaphyseal lesions of 1 2 mm to several cm with fine sclerotic margins + relative sparing of medullary cavity

    • may show overgrowth of long bone

    • endosteal thickening

    • sometimes associated with soft-tissue mass phleboliths

    • chylous pleural effusion suggests fatal prognosis

      DDx: (other polyostotic diseases such as) histiocytosis X, fibrous dysplasia, metastases, Gaucher disease, congenital fibromatosis, Maffucci syndrome, neurofibromatosis, enchondromatosis

  • SOFT-TISSUE ANGIOMATOSIS (60 70%)

    • = VISCERAL ANGIOMATOSIS

    • poor prognosis

  • ANGIOMATOUS SYNDROMES

    • Maffucci syndrome

    • Osler-Weber-Rendu syndrome

    • Klippel-Trenaunay-Weber disease

    • Kasabach-Merritt syndrome

    • Gorham disease

Angiosarcoma

= aggressive vascular malignancy with frequent local recurrence + distant metastasis

Histo: vascular channels surrounded by hemangiomatous / lymphomatous cellular elements with high degree of anaplasia
Age: M:F = 2:1
Associated with: Stewart-Treves syndrome

= angiosarcoma with chronic lymphedema developing in postmastectomy patients

Location: skin (33%); soft tissue (24%); bone (6%): tibia (23%), femur (18%), humerus (13%), pelvis (7%)
DDx: hemangioendothelioma, hemangiopericytoma

Ankylosing Spondylitis

= autoimmune disease of unknown etiology primarily affecting axial skeleton

Age: 15 35 years; M:F = 3:1 10:1; Caucasians:Blacks = 3:1
Associated with: (1) ulcerative colitis, regional enteritis
(2) iritis in 25%
(3) aortic insufficiency + atrioventricular conduction defect

  • HLA-B 27 positive in 96%

  • insidious onset of low back pain + stiffness

    Path: involves synovial + cartilaginous joints and sites of ligamentous attachment

    Location:

    • axial skeleton: sacroiliac joints, thoracolumbar + lumbosacral junctions

      • HALLMARK is sacroiliac joint involvement!

    • peripheral skeleton (10 20%): sternal joint, symphysis pubis, hip, glenohumeral joint

    • tendinous insertions in pelvis + proximal femur

    Temporal course: initial abnormalities of sacroiliac joints + thoracolumbar junction with gradual involvement of remainder of spine

P.47


  • @ Skull

    • temporomandibular joint space narrowing, erosions, osteophytosis

  • @ Hand (30%)

    Target area: MCP, PIP, DIP

    • exuberant osseous proliferation

    • osteoporosis, joint space narrowing, osseous erosions (deformities less striking than in rheumatoid arthritis)

  • @ Sacroiliac joint / symphysis pubis

    • initially sclerosis of joint margins primarily on iliac side (bilateral + symmetric late in disease, may be unilateral + asymmetric early in disease)

    • later irregularities + widening of joint (cartilage destruction)

    • bony fusion

  • @ Pelvis

    • periostitic whiskering : ischial tuberosity, iliac crest, ischiopubic rami, greater femoral trochanter, external occipital protuberance, calcaneus

  • @ Spine

    • squaring = straightened / convex anterior vertebral margins = erosive osteitis of anterior corners

    • shiny corner = reactive sclerosis of corners of vertebral bodies

    • diskitis = erosive abnormalities of diskovertebral junction

    • diskal ballooning = biconvex shape of intervertebral disk related to osteoporotic deformity diskal calcification

    • marginal syndesmophyte formation = thin vertical radiodense spicules bridging the vertebral bodies = ossification of outer fibers of annulus fibrosus (NOT anterior longitudinal ligament):

      • bamboo spine on AP view = undulating contour due to syndesmophytosis

        Cx: prone to fracture resulting in pseudarthrosis

    • asymmetric erosions of laminar + spinous processes of lumbar spine

    • ossification of supraspinous + interspinous ligaments:

      • dagger sign = single radiodense line on AP view

      • trolley-track sign on AP view = central line of ossification with two lateral lines of ossification (apophyseal joint capsules)

    • apophyseal + costovertebral joint ankylosis (on oblique views)

    • dorsal arachnoid diverticula in lumbar spine with erosion of posterior elements (Cx: cauda equina syndrome)

    • atlantoaxial subluxation

  • @ Chest

    Incidence: 1% of patients with ankylosing spondylitis
    Histo: interstitial + pleural fibrosis with foci of dense collagen deposition, NO granulomas

    • bone manifestations obvious + severe

      Location: apices / upper lung fields

    • sternomanubrial joint irregularities + sclerosis

    • uni- / bilateral coarse upper lobe pulmonary fibrosis with upward retraction of hila (DDx: tuberculosis)

    • reticulonodular progressively confluent opacities in lung apices

    • apical bullae + cavitation (mimicking TB)

    • HRCT:

      • peripheral interstitial lung disease

      • bronchiectasis

      • paraseptal emphysema

      • apical fibrosis

      Cx: superinfection, especially with aspergillosis (mycetoma formation) / atypical mycobacteria
      DDx: other causes of pulmonary apical fibrosis (primary infection by fungi / mycobacteria; cancer)

  • @ Cardiovascular

    • Aortitis (5%) of ascending aorta aortic valve insufficiency

    Prognosis: 20% progress to significant disability; occasionally death from cervical spine fracture / aortitis
    DDx: (1) Reiter syndrome (unilateral asymmetric SI joint involvement, paravertebral ossifications)
    (2) Psoriatic arthritis (unilateral asymmetric SI joint involvement, paravertebral ossifications)
    (3) Inflammatory bowel disease
    (4) Sternocostoclavicular hyperostosis (pustulosis palmaris et plantaris)

Anterior Tibial Bowing

  • = WEISMANN-NETTER SYNDROME

  • = congenital painless nonprogressive bilateral anterior leg bowing

    Age: beginning in early childhood

  • may be accompanied by mental retardation, goiter, anemia

  • anterior bowing of tibia + fibula, bilaterally, symmetrically at middiaphysis

  • thickening of posterior tibial + fibular cortices

  • minor radioulnar bowing

  • kyphoscoliosis

  • extensive dural calcification

    DDx: Luetic saber shin (bowing at lower end of tibia + anterior cortical thickening)

Apert Syndrome

= ACROCEPHALOSYNDACTYLY type I

Frequency: 5.5:1,000,000 neonates
Etiology: autosomal dominant with incomplete penetrance; sporadic (in majority)

Associated with CNS anomalies:

  • megalocephaly, gyral abnormalities, hypoplastic white matter, heterotopic gray matter, frontal encephalocele, corpus callosal agenesis, Kleeblattsch del, cleft palate, ventriculomegaly (? related to skull base hypoplasia, rarely progressive)

  • IQ varies depending on CNS anomalies (in 50% normal)

  • otitis media (high prevalence)

  • bifid uvula

  • conductive hearing loss (common due to external + middle ear malformations)

  • @ Skull

    • downturned mouth

    • brachycephalic skull (due to coronal craniosynostosis) + flat occiput

    • widened metopic + sagittal sutures extending from glabella to posterior fontanel (closing between 2 to 4 years)

    • hypoplastic / retruded midface:

      • hypertelorism

      • shallow orbits with proptosis

        • P.48


      • underdeveloped paranasal sinuses

      • underdeveloped maxilla with prognathism

    • high pointed arch of palate

    • prominent vertical crest in middle of forehead (increased intracranial pressure)

    • V-shaped anterior fossa due to elevation of lateral margins of lesser sphenoid

    • sella may be enlarged

    • stylohyoid ligament calcification (38 88%)

    • cervical spine fusion (in up to 71%), commonly of 5th and 6th vertebrae

    • choanal stenosis

  • @ Hand & feet

    • severe symmetric syndactyly = fusion of distal portions of phalanges, metacarpals / carpals (most often of 2nd, 3rd + 4th digit)

    • absence of middle phalanges

    • missing / supernumerary carpal / tarsal bones

    • pseudarthroses

  • @ GU (10%)

    • cryptorchidism

    • hydronephrosis

    • polycystic kidneys (rare)

    • bicornuate uterus (rare)

Arteriovenous Fistula of Bone

Etiology: (a) acquired (usually gunshot wound)
(b) congenital
Location: lower extremity most frequent

  • soft-tissue mass

  • presence of large vessels

  • phleboliths (DDx: long-standing varicosity)

  • accelerated bone growth

  • cortical osteolytic defect (= pathway for large vessels into medulla)

  • increased bone density

Arthrogryposis

  • = ARTHROGRYPOSIS MULTIPLEX CONGENITA

  • = nonprogressive congenital syndrome complex characterized by poorly developed + contracted muscles, deformed joints with thickened periarticular capsule and intact sensory system

Pathophysiology: congenital / acquired defect of motor unit (anterior horn cells, nerve roots, peripheral nerves, motor end plates, muscle) early in fetal life with immobilization of joints at various stages in their development
Cause: ? neurotropic agents, toxic chemicals, hard drugs, hyperthermia, neuromuscular blocking agents, mytotic abnormalities, mechanical immobilization
Incidence: 0.03% of newborn infants; 5% risk of recurrence in sibling
Path: diminution in size of muscle fibers + fat deposits in fibrous tissue
Associated with: (1) neurogenic disorders (90%)
(2) myopathic disorders
(3) skeletal dysplasias
(4) intrauterine limitation of movement (myomata, amniotic band, twin, oligohydramnios)
(5) connective tissue disorders
Distribution: all extremities (46%), lower extremities only (43%), upper extremities only (11%); peripheral joints >> proximal joints; symmetrical

  • clubfoot

  • congenital dislocation of hip

  • claw hand

  • diminished muscle mass

  • skin webs

  • flexion + extension contractures

  • osteopenia pathologic fractures

  • congenital dislocation of hip

  • carpal coalition

  • vertical talus

  • calcaneal valgus deformity

Asphyxiating Thoracic Dysplasia

  • = JEUNE DISEASE

  • = autosomal recessive dysplasia

    Incidence: 100 cases
    Associated with: renal anomalies (hydroureter), PDA

  • respiratory distress due to reduced thoracic mobility (abdominal breathing) + frequent pulmonary infections

  • progressive renal failure + hypertension

  • @ Chest

    • markedly narrow + elongated bell-shaped chest:

      • chest diameter significantly decreased compared with that of the abdomen

    • normal size of heart leaving little room for lungs

    • horizontal clavicles at level of 6th cervical vertebra

    • short horizontal ribs + irregular bulbous costochondral junction

  • @ Pelvis

    • trident pelvis (retardation of ossification of triradiate cartilage)

    • small iliac wings flared + shortened in cephalocaudal diameter ( wineglass pelvis)

    • short ischial + pubic bones

    • reduced acetabular angle + acetabular spurs

    • premature ossification of capital femoral epiphysis

  • @ Extremities

    • rhizomelic brachymelia (humerus, femur) = long bones shorter + wider than normal

    • metaphyseal irregularity

    • postaxial hexadactyly (occasionally)

    • shortening of distal phalanges + cone-shaped epiphyses in hands + feet

    • proximal humeral + femoral epiphyses ossified at birth (frequently)

  • @ Kidneys

    • medullary cystic renal disease = enlarged kidneys with linear streaking on nephrogram (in adulthood)

    • OB-US:

      • proportionate shortening of long bones

      • small thorax with decreased circumference

      • increased cardiothoracic ratio

      • occasionally polydactyly

      • polyhydramnios

      Prognosis: neonatal death in 80% (respiratory failure + infections)
      DDx: Ellis-van Creveld syndrome

Avascular Necrosis

  • = AVN = OSTEONECROSIS = ASEPTIC NECROSIS

  • = consequence of interrupted blood supply to bone with death of cellular elements

Terminology (now often used interchangeably):

  • Osteonecrosis = ischemic bone death due to sepsis

  • Avascular necrosis = avascular and aseptic bone necrosis

  • Ischemic necrosis = necrosis of epiphyseal + subarticular bone

  • Bone infarction = necrosis of metaphyseal + diaphyseal bone

Histo:

  • cellular ischemia leading to death of hematopoietic cells (in 6 12 hours), osteocytes (in 12 48 hours) and lipocytes (in 2 5 days)

  • necrotic debris in intertrabecular spaces + proliferation and infiltration by mesenchymal cells + capillaries

  • mesenchymal cells differentiate to osteoblasts on the surface of dead trabeculae synthesizing new bone layers + resulting in trabecular thickening

Pathogenesis:

  • obstruction of extra- and intraosseous vessels by arterial embolism, venous thrombosis, traumatic disruption, external compression (increased marrow space pressure)

  • cumulative stress from cytotoxic factors

Cause:

  • NO predisposing factors in 25%!

  • Traumatic interruption of arteries

    • @ femoral head:

      • Femoral neck fracture (60 75%)

      • Dislocation of hip joint (25%)

      • Slipped capital femoral epiphysis (15 40%)

    • @ carpal scaphoid:

      • 4 6 months after fracture (in 10 15%), in 30 40% of nonunion of scaphoid fracture

        Site: proximal fragment (most common)

    • @ humeral head (infrequent)

    • @ talus (after talar neck fracture)

  • Embolization of arteries

    • Hemoglobinopathy: sickle-cell disease

    • Nitrogen bubbles: Caisson disease

    • Fat: ethanol abuse with pancreatitis

  • Vasculitis

    • Collagen-vascular disease: SLE

    • Radiation exposure

  • Abnormal accumulation of cells

    • Lipid-containing histiocytes: Gaucher disease

    • Fat cells: steroid therapy

  • Idiopathic

    • Spontaneous osteonecrosis of knee

    • Legg-Calv -Perthes disease

    • Freiberg disease (repetitive microtrauma)

mnemonic: PLASTIC RAGS

  • Pancreatitis, Pregnancy

  • Legg-Perthes disease, Lupus erythematosus

  • Alcoholism, Atherosclerosis

  • Steroids

  • Trauma (femoral neck fracture, hip dislocation)

  • Idiopathic (Legg-Perthes disease), Infection

  • Caisson disease, Collagen disease (SLE)

  • Rheumatoid arthritis, Radiation treatment

  • Amyloid

  • Gaucher disease

  • Sickle cell disease

mnemonic: GIVE INFARCTS

  • Gaucher disease

  • Idiopathic (Legg-Calv -Perthes, K hler, Chandler)

  • Vasculitis (SLE, polyarteritis nodosa, rheumatoid arthritis)

  • Environmental (frostbite, thermal injury)

  • Irradiation

  • Neoplasia (-associated coagulopathy)

  • Fat (prolonged corticosteroid use increases marrow)

  • Alcoholism

  • Renal failure + dialysis

  • Caisson disease

  • Trauma (femoral neck fracture, hip dislocation)

  • Sickle cell disease

Location: femoral head (most common), humeral head, femoral condyles

Radiography:

  • dense osteonecrotic bone (due to lack of resorption relative to healthy osteopenic bone + new bone laid down over necrotic trabeculae)

  • radiolucent rim around area of osteonecrosis (due to absorption around necrotic bone)

Avascular Necrosis of Hip

  • Involvement of one hip increases risk to contralateral hip to 70%!

    Age: 20 50 years

  • hip / groin / thigh / knee pain

  • limited range of motion

Plain film (positive only several months after symptoms):

  • subtle relative sclerosis of femoral head secondary to resorption of surrounding vascularized bone (earliest sign)

  • radiolucent crescent parallel to articular surface in weight-bearing portion secondary to subchondral structural collapse of necrotic segment

    Site: anterosuperior portion of femoral head (best seen on frog leg view)

  • preservation of joint space (DDx: arthritis)

  • flattening of articular surface

  • increased density of femoral head (compression of bony trabeculae following microfracture of nonviable bone, calcification of dendritic marrow, creeping substitution = deposition of new bone)

Classification (Steinberg):

P.49


P.50


Stage 0 = normal
Stage I = normal / barely detectable trabecular mottling; abnormal bone scan / MRI
Stage IIA = focal sclerosis + osteopenia
Stage IIB = distinct sclerosis + osteoporosis + early crescent sign
Stage IIIA = subchondral undermining ( crescent sign ) + cyst formation
Stage IIIB = mild alteration in femoral head contour / subchondral fracture + normal joint space
Stage IV = marked collapse of femoral head + significant acetabular involvement
Stage V = joint space narrowing + acetabular degenerative changes

NUC (80 85% sensitivity):

  • Bone marrow imaging (with radiocolloid) more sensitive than bone imaging (with diphosphonates)

  • More sensitive than plain films in early AVN (evidence of ischemia seen as much as 1 year earlier)

  • Less sensitive than MR

Technique: imaging improved with double counts, pinhole collimation

  • early: cold = photopenic defect (interrupted blood supply)

  • late: doughnut sign = cold spot surrounded by increased uptake secondary to

    • capillary revascularization + new-bone synthesis

    • degenerative osteoarthritis

CT (utilized for staging of known disease):

  • staging upgrades in 30% compared with plain films

MR (90 100% sensitive, 85% specific for symptomatic disease):

Prevalence of clinically occult disease: 6%

  • MR imaging changes reflect the death of marrow fat cells (not death of osteocytes with empty lacunae)!

  • Sagittal images particularly useful!

  • EARLY AVN:

    • decreased Gd-enhancement on short-inversion-recovery (STIR) images (very early)

    • low-signal intensity band with sharp inner interface + blurred outer margin on T1WI within 12 48 hours (= mesenchymal + fibrous repair tissue, amorphous cellular debris, thickened trabecular bone) seen as

      • band extending to subchondral bone plate

      • complete ring (less frequent)

    • double-line sign on T2WI (in 80%) [MORE SPECIFIC] = juxtaposition of inner hyperintense band (granulation tissue) + outer hypointense band (chemical shift artifact / fibrosis + sclerosis)

  • ADVANCED AVN:

    • pseudohomogeneous edema pattern = inhomogeneous large areas of mostly decreased signal intensity on T1WI

    • hypo- to hyperintense lesion on T2WI

    • contrast-enhancement of interface + surrounding marrow + within lesion

  • SUBCHONDRAL FRACTURE:

    • predilection for anterosuperior portion of femoral head (sagittal images!)

      MRI Classification of Aseptic Necrosis Mitchell Classification

      Stage T1 T2 Analogous to
      A high intermediate fat
      B high high subacute blood
      C low high fluid / edema
      D low low fibrosis

    • cleft of low-signal intensity running parallel to the subchondral bone plate within areas of fatlike signal intensity on T1WI

    • hyperintense band (= fracture cleft filled with articular fluid / edema) within the intermediate- or low-signal-intensity necrotic marrow on T2WI

    • lack of enhancement within + around fracture cleft

  • EPIPHYSEAL COLLAPSE:

    • focal depression of subchondral bone

      Cx: early osteoarthritis through collapse of femoral head + joint incongruity in 3 5 years if left untreated
      Rx: (1) core decompression (for grade 0 II): most successful with <25% involvement of femoral head
      (2) osteotomy (for grade 0 II)
      (3) arthroplasty / arthrodesis / total hip replacement (for grade >III)
      DDx: bone marrow edema (ill-delimited marrow changes, no reactive interface); epiphyseal fracture (speckled / linear hypointense areas, focal depression of epiphyseal contour); spondyloarthropathy

Blount Disease

  • = TIBIA VARA

  • = avascular necrosis of medial tibial condyle

    Age: >6 years

  • limping, lateral bowing of leg

  • medial tibial condyle enlarged + deformed (DDx: Turner syndrome)

  • irregularity of metaphysis (medially + posteriorly prolonged with beak)

Calv -K mmel-Verneuil Disease

  • = VERTEBRAL OSTEOCHONDROSIS = VERTEBRA PLANA

  • = avascular necrosis of vertebral body

    Age: 2 15 years

  • uniform collapse of vertebral body into flat thin disk

  • increased density of vertebra

  • neural arches NOT affected

  • disks are normal with normal intervertebral disk space

  • intravertebral vacuum cleft sign (PATHOGNOMONIC)

    DDx: eosinophilic granuloma, metastatic disease

Freiberg Disease

[Albert Henry Freiberg (1868 1940), orthopedic surgeon in Cincinnati, Ohio]

= osteochondrosis of head of 2nd (3rd / 4th) metatarsal

Age: 10 18 years; M:F = 1:3

  • metatarsalgia, swelling, tenderness

Early:

  • flattening, increased density, cystic lesions of metatarsal head

  • widening of metatarsophalangeal joint

Late:

  • osteochondral fragment

  • sclerosis + flattening of metatarsal head

  • increased cortical thickening

Kienb ck Disease

  • = LUNATOMALACIA

  • [Robert Kienb ck (1871 1953), radiologist in Vienna, Austria]

  • = avascular necrosis of lunate bone

    P.51


    Predisposed: individuals engaged in manual labor with repeated/single episode of trauma
    Age: 20 40 years
    Associated with: ulna minus variant (short ulna) in 75%

  • progressive pain + soft-tissue swelling of wrist

    Location: uni- > bilateral (usually right hand)

  • initially normal radiograph

  • osteonecrotic fracture of carpal lunate

  • increased density + altered shape + collapse of lunate

    Cx: scapholunate separation, ulnar deviation of triquetrum, degenerative joint disease in radiocarpal / midcarpal compartments
    Rx: ulnar lengthening / radial shortening, lunate replacement

K hler Disease

  • = avascular necrosis of tarsal scaphoid

    Age: 3 10 years; boys

  • irregular outline

  • fragmentation

  • disklike compression in AP direction

  • increased density

  • joint space maintained

  • decreased / increased uptake on radionuclide study

Legg-Calv -Perthes Disease

  • = COXA PLANA

  • = idiopathic avascular necrosis of femoral head in children; one of the most common sites of AVN;

    in 5 10% bilateral

    Age: (a) 2 12 (peak, 4 8) years: M:F = 5:1
    (b) adulthood: Chandler disease
    Cause: trauma in 30% (subcapital fracture, epiphyseolysis, esp. posterior dislocation), closed reduction of congenital hip dislocation, prolonged interval between injury and reduction

    Pathophysiology:

    insufficient femoral head blood supply (epiphyseal plate acts as a barrier in ages 4 10; ligamentum teres vessels become nonfunctional; blood supply is from medial circumflex artery + lateral epiphyseal artery only)

    Stages:

    I = histologic + clinical diagnosis without radiographic findings
    II = sclerosis cystic changes with preservation of contour + surface of femoral head
    III = loss of structural integrity of femoral head
    IV = in addition loss of structural integrity of acetabulum

    • 1 week 6 months (mean 2.7 months) duration of symptoms prior to initial presentation: limp, pain

  • NUC (may assist in early diagnosis):

    • decreased uptake (early) in femoral head = interruption of blood supply

    • increased uptake (late) in femoral head =

      • revascularization + bone repair

      • degenerative osteoarthritis

    • increased acetabular activity with associated degenerative joint disease

    X-RAY:

    • Early signs:

      • femoral epiphysis smaller than on contralateral side (96%)

      • sclerosis of femoral head epiphysis (sequestration + compression) (82%)

      • slight widening of joint space due to thickening of cartilage, failure of epiphyseal growth, presence of joint fluid, joint laxity (60%)

      • ipsilateral bone demineralization (46%)

      • alteration of pericapsular soft-tissue outline due to atrophy of ipsilateral periarticular soft tissues (73%)

      • rarefaction of lateral + medial metaphyseal areas of neck

      • NEVER destruction of articular cortex as in bacterial arthritis

    • Late signs:

      • delayed osseous maturation of a mild degree

      • radiolucent crescent line of subchondral fracture = small archlike subcortical lucency (32%)

      • subcortical fracture on anterior articular surface (best seen on frog leg view)

      • femoral head fragmentation

      • femoral neck cysts (from intramedullary hemorrhage in response to stress fractures)

      • loose bodies (only found in males)

    • Regenerative signs:

      • coxa plana = flattened collection of sclerotic fragments (over 18 months)

      • coxa magna = remodeling of femoral head to become wider + flatter in mushroom configuration to match widened metaphysis + epiphyseal plate

    CT:

    • loss of asterisk sign (= starlike pattern of crossing trabeculae in center of femoral head) with distortion of asterisk and extension to surface of femoral head

    MR:

    • normal signal intensity in marrow of femoral epiphysis replaced by low signal intensity on T1WI + high signal intensity on T2WI = asterisk sign

    • double-line sign (80%) = sclerotic nonsignal rim producing line between necrotic + viable bone edged by a hyperintense rim of granulation tissue

    • fluid within fracture plane

    • hip joint incongruity: lateral femoral head uncovering, labral inversion, femoral head deformity

    Cx: severe degenerative joint disease in early adulthood
    Rx: bed rest, abduction bracing (to reduce stress on infarcted head)

Panner Disease

  • (NOT osteonecrosis)

  • = benign self-limited disorder of fragmented ossification in epiphysis of capitellum

    Age: children 7 12 years of age

Preiser Disease

  • = nontraumatic osteonecrosis of scaphoid

P.52


Spontaneous Osteonecrosis of Knee

= SONK

Cause: ? meniscal tear (78%), trauma with resultant microfractures, vascular insufficiency, degenerative joint disease, severe chondromalacia, gout, rheumatoid arthritis, joint bodies, intraarticular steroid injection (45 85%)
Age: 7th decade (range 13 83 years)

  • acute onset of pain

Location: weight-bearing medial condyle more toward epicondylus (95%), lateral condyle (5%), may involve tibial plateau

  • radiographs usually normal (within 3 months after onset)

  • positive bone scan within 5 weeks (most sensitive)

  • flattening of weight-bearing segment of medial femoral epicondyle

  • radiolucent focus in subchondral bone + peripheral zone of osteosclerosis

  • horizontal subchondral fracture (within 6 9 months) + osteochondral fragment

  • periosteal reaction along medial side of femoral shaft (30 50%)

    Cx: osteoarthritis

Talar AVN

  • Fractures involving the talar body have a higher prevalence of AVN

  • Risk of AVN:

    • nondisplaced fracture

      - talar neck fracture (Hawkins type I) 0 15%

    • fracture with dislocation / subluxation of:

      - subtalar joint (Hawkins type II) 20 50%
      - ankle + subtalar joints (Hawkins type III) almost 100%
      - subtalar + tibiotalar + talonavicular joints (Hawkins type IV fracture) 100%

  • increase in talar dome opacity / sclerosis

  • deformity + articular collapse + bone fragmentation

  • absent Hawkins sign = thin subchondral radiolucent line along talar dome (due to disuse osteopenia) indicates an adequate blood supply

Basal Cell Nevus Syndrome

  • = NEVOID BASAL CELL CARCINOMA SYNDROME = GORLIN SYNDROME

  • = syndrome of autosomal dominant inheritance characterized by

    • multiple cutaneous basal cell carcinomas during childhood

    • odontogenic keratocysts of mandible

    • ectopic calcifications

    • skeletal anomalies

  • multiple nevoid basal cell carcinomas (nose, mouth, chest, back) at mean age of 19 years; after puberty aggressive, may metastasize

  • pitlike defects in palms + soles

  • mental retardation

Association: high incidence of medulloblastoma in children; ovarian fibroma (in 17%); cardiac fibroma (in 14%)

  • @ mandibular hypoplasia:

    • multiple mandibular + maxillary cysts (dentigerous cysts + ectopic dentition)

  • anomalies of upper 5 ribs:

    • forked = bifid rib (most commonly 4th rib)

    • agenesis / supernumerary ribs

    • fusion of adjacent ribs

    • dysplastic distorted ribs

  • bifid spinous processes, spina bifida

  • scoliosis (cervical + upper thoracic)

  • hemivertebrae + block vertebrae

  • Sprengel deformity (scapula elevated, hypoplastic, bowed)

  • deficiency of lateral clavicle

  • brachydactyly

  • extensive calcification of falx + tentorium

  • ectopic calcifications of subcutaneous tissue, ovaries, sacrotuberous ligaments, mesentery

  • bony bridging of sella turcica

  • macrocephaly

Battered Child Syndrome

  • = CAFFEY-KEMPE SYNDROME = CHILD ABUSE = PARENT -INFANT TRAUMATIC STRESS SYNDROME = NON-ACCIDENTAL TRAUMA

  • Most common cause of serious intracranial injuries in children <1 year of age; 3rd most common cause of death in children after sudden infant death syndrome + true accidents

    Prevalence: 1.7 million cases reported + 833,000 substantiated in United States in 1990 (45% neglected children, 25% physically abused, 16% sexually abused children); resulting in 2,500 5,000 deaths/year; 5 10% of children seen in emergency rooms
    Age: usually <2 years

  • skin burns, bruising, lacerations, hematomas (SNAT = suspected nonaccidental trauma)

  • @ Skeletal trauma (50 80%)

    Site: multiple ribs, costochondral / costovertebral separation, acromion, skull, anterior-superior wedging of vertebra, tibia, metacarpus
    Unusual sites: transverse fracture of sternum, lateral end of clavicles, scapula, vertebral compression, vertebral fracture dislocation, disk space narrowing, spinous processes
    Other clues: bilateral acute fractures, fractures of lower extremities in children not yet walking

    • multiple asymmetric fractures in different stages of healing (repeated injury = HALLMARK)

    • exuberant callus formation at fracture sites

    • avulsion fracture of ligamentous insertion; frequently seen without periosteal reaction

    • @ Epiphysis

      • separation of distal epiphysis

    • @ Metaphysis

      • marked irregularity + fragmentation of metaphyses (DDx: osteochondritis stage of congenital syphilis; infractions of scurvy)

      • corner fracture (11%) = bucket-handle fracture

        = avulsion of an arcuate metaphyseal fragment overlying the lucent epiphyseal cartilage

        P.53


        Cause: sudden twisting motion of extremity (periosteum easily pulled away from diaphysis but tightly attached to metaphysis)
        Location: knee, elbow, distal tibia, fibula, radius, ulna

    • @ Diaphysis

      • isolated spiral fracture (15%) of diaphysis secondary to external rotatory force applied to femur / humerus

      • extensive periosteal reaction from large subperiosteal hematoma apparent after 7 14 days following injury (DDx: scurvy, copper deficiency)

      • cortical hyperostosis extending to epiphyseal plate (DDx: not in infantile cortical hyperostosis)

  • @ Head trauma (13 25%)

    • Most common cause of death + physical disability!

      • Impact injury with translational force: skull fracture (flexible calvaria + meninges decrease likelihood of skull fractures), subdural hematoma, brain contusion, cerebral hemorrhage, infarction, generalized edema

      • Whiplash injury with rotational force: shearing injuries + associated subarachnoid hemorrhage

    • bulging fontanels, convulsions

    • ocular lesions, retinal detachment

    • Skull film (associated fracture in 1%):

      • linear fracture > comminuted fracture > diastases (conspicuously absent)

    • CT:

      • subdural hemorrhage (most common): interhemispheric location most common

      • subarachnoid hemorrhage

      • epidural hemorrhage (uncommon)

      • cerebral edema (focal, multifocal, diffuse)

      • acute cerebral contusion as ovoid collection of intraparenchymal blood with surrounding edema

    • MR:

      • More sensitive in identifying hematomas of differing ages

      • white matter shearing injuries as areas of prolonged T1 + T2 at corticomedullary junction, centrum semiovale, corpus callosum

  • @ Viscera (3%)

    • Second leading cause of death in child abuse

    Cause: crushing blow to abdomen (punch, kick)
    Age: often >2 years

    • small bowel / gastric rupture

    • hematoma of duodenum / jejunum

    • contusion / laceration of lung, pancreas, liver, spleen, kidneys

    • traumatic pancreatic pseudocyst

Cx: (1) Brain atrophy (up to 100%)
(2) Infarction (50%)
(3) Subdural hygroma
(4) Encephalomalacia
(5) Porencephaly
DDx: normal periostitis of infancy, long-term ventilator therapy in prematurity, osteogenesis imperfecta, congenital insensitivity to pain, infantile cortical hyperostosis, Menkes kinky hair syndrome, Schmid-type chondrometaphyseal dysplasia, scurvy, congenital syphilitic metaphysitis

Benign Cortical Defect

= developmental intracortical bone defect

Age: usually 1st 2nd decade; uncommon in boys <2 years of age; uncommon in girls <4 years of age

  • asymptomatic

    Site: metaphysis of long bone

  • well-defined intracortical round / oval lucency

  • usually <2 cm long

  • sclerotic margins

Cx: pathologic / avulsion fracture following minor trauma (infrequent)
Prognosis: (1) Spontaneous healing resulting in sclerosis / disappearance
(2) Ballooning of endosteal surface of cortex = fibrous cortical defect
(3) Medullary extension resulting in nonossifying fibroma

Bone Infarct

Etiology:

  • Occlusion of vessel:

    • thrombus: thromboembolic disease, sickle cell disease (SS + SC hemoglobin), polycythemia rubra vera

    • fat: pancreatitis (intramedullary fat necrosis from circulating lipase), alcoholism

    • gas: Caisson disease, astronauts

  • Vessel wall disease:

    • Arteritis: SLE, rheumatoid arthritis, polyarteritis nodosa, sarcoidosis

    • Arteriosclerosis

  • Vascular compression by deposition of:

    • fat: corticosteroid therapy (eg, renal transplant, Cushing disease)

    • blood: trauma (fractures + dislocations)

    • inflammatory cells: osteomyelitis, infection, histiocytosis X

    • edema: radiation therapy, hypothyroidism, frostbite

    • substances: Gaucher disease (vascular compression by lipid-filled histiocytes), gout

  • Others: idiopathic, hypopituitarism, pheochromocytoma (microscopic thrombotic disease), osteochondroses

Medullary Infarction

  • Nutrient artery is the sole blood supply for diaphysis!

Location: distal femur, proximal tibia, iliac wings, ribs, humeri

  • Acute phase:

    • NO radiographic changes without cortical involvement

    • area of rarefaction

    • infarcted area hypointense on T1WI + hyperintense on T2WI

    • bone marrow scan: diminished uptake in medullary RES for long period of time

    • bone scan: photon-deficient lesion within 24 48 hours; increased uptake after collateral circulation established

  • Healing phase (complete healing / fibrosis / calcification):

    • demarcation by zone of serpiginous / linear calcification + ossification parallel to cortex

    • dense bone indicating revascularization

      • P.54


    • focal lesion with fatty marrow signal intensity centrally + surrounding hypointense rim (corresponding to reactive / sclerotic bone)

Cortical Infarction

  • Requires compromise of (a) nutrient artery and (b) periosteal vessels!

    Age: particularly in childhood where periosteum is easily elevated by edema

  • avascular necrosis = osteonecrosis

  • osteochondrosis dissecans

Cx: (1) Growth disturbances
    cupped / triangular / coned epiphyses
    H-shaped vertebral bodies
(2) Fibrosarcoma (most common), malignant fibrous histiocytoma, benign cysts
(3) Osteoarthritis

Bone Island

  • = ENOSTOSIS = ENDOSTEOMA = COMPACT ISLAND

    • = FOCAL SCLEROSIS = SCLEROTIC BONE ISLAND

    • = CALCIFIED MEDULLARY DEFECT

  • = focal lesion of densely sclerotic (compact) bone nesting within spongiosa

Age: any age (mostly 20 80 years of age); grows more rapidly in children
Histo: nest of lamellar compacted bone with haversian system embedded within medullary canal
Pathogenesis: ? misplaced cortical hamartoma,? developmental error of endochondral ossification as a coalescence of mature bone trabeculae with failure to undergo remodeling; not inherited
asymptomatic  
Location: ilium + proximal femur (88 92%), ribs, spine (1 14%), humerus, phalanges (not in skull)

  • round / oval / oblong solitary osteoblastic lesion with abrupt transition to surrounding normal trabecular bone

  • long axis of bone island parallels long axis of bone

  • usually 2 10 mm in size; lesion >2 cm in longest axis = giant bone island

  • brush border = thorny radiations = sharply demarcated margins with feathery peripheral radiations (HALLMARK) blending with trabeculae of surrounding spongiosa

  • may show activity on bone scan, esp. if large (33%)

  • may demonstrate slow growth / decrease in size (32%)

  • NO involvement of cortex / radiolucencies / periosteal reaction

Prognosis: may increase to 8 12 cm over years (40%); may decrease / disappear
DDx: (1) Osteoblastic metastasis (aggressive, break through cortex, periosteal reaction)
(2) Low-grade osteosarcoma (cortical thickening, extension beyond medullary cavity)
(3) Osteoid osteoma (pain relieved by aspirin, nidus)
(4) Benign osteoblastoma
(5) Involuted nonossifying fibroma replaced by dense bone scar
(6) Eccentric focus of monostotic fibrous dysplasia
(7) Osteoma (surface lesion)

Brucellosis

= multisystemic zoonosis of worldwide distribution; endemic in Saudi Arabia, Arabian Peninsula, South America, Spain, Italy (secondary to ingestion of raw milk / milk products)

Organism: small gram-negative nonmotile, nonsporing, aflagellate, nonencapsulated coccobacilli: Brucella abortus, B. suis, B. canis, B. melitensis
Histo: small intracellular pathogens shed in excreta of infected animals (urine, stool, milk, products of conception) cause small noncaseating granuloma within RES
Location: commonest site of involvement is reticulo-endothelial system; musculoskeletal system

  • 1 3 weeks between initial infection + symptoms

    • Radiologic evidence of disease in 69% of symptomatic sites!

  • Brucellar spondylitis (53%)

    Age: 40 years is average age at onset

    • pain, localized tenderness, radiculopathy, myelopathy

    Location: lumbar (71%) > thoracolumbar (10%) > lumbosacral (8%) > cervical (7%) > thoracic (4%)

    • focal form

      • bone destruction at diskovertebral junction (anterior aspect of superior endplate)

      • associated with bone sclerosis + anterior osteophyte formation + small amount of gas

    • diffuse form: entire vertebral endplate / whole vertebral body affected with spread to adjacent disks + vertebral bodies

      • bone destruction associated with sclerosis

      • small amount of disk gas (25 30%)

      • obliteration of paraspinal muscle-fat planes

      • no / minimal epidural extension

        DDx: TB (paraspinal abscess, gibbus)

  • @ Extraspinal disease

    • Brucellar synovitis (81%)

      Location: knee > sacroiliac joint > shoulder > hip > sternoclavicular joint > ankle > elbow
      Site: organism localized in synovial membrane

      • serosanguinous sterile joint effusion

    • Brucellar destructive arthritis (9%)

      • indistinguishable from tuberculous / pyogenic arthritis

    • Brucellar osteomyelitis (2%)

      • pain, tenderness, swelling

    • Brucellar myositis (2%)

Dx: serologic tests (enzyme-linked immunosorbent assay, counterimmunoelectrophoresis, rose bengal plate test
Rx: combination of aminoglycosides + tetracyclines
DDx: fibrous dysplasia, benign tumor, osteoid osteoma

Caisson Disease

= DECOMPRESSION SICKNESS = THE BENDS

Etiology: during too rapid decompression = reduction of surrounding pressure (ascent from dive, exit from caisson / hyperbaric chamber, ascent to altitude) nitrogen bubbles form (nitrogen more soluble in fat of panniculus adiposus, spinal cord, brain, bones containing fatty marrow)

  • the bends = local pain in knee, elbow, shoulder, hip

  • neurologic symptoms (paresthesia, major cerebral / spinal involvement)

    • P.55


  • chokes = substernal discomfort + coughing (embolization of pulmonary vessels)

    Location: mostly in long tubular bones of lower extremity (distal end of shaft + epiphyseal portion); symmetrical lesions

  • early: area of rarefaction

  • healing phase: irregular new-bone formation with greater density

  • peripheral zone of calcification / ossification

  • ischemic necrosis of articular surface with secondary osteoarthritis

Calcium Pyrophosphate Dihydrate Crystal Deposition Disease

  • = CPPD = PSEUDOGOUT = FAMILIAL CHONDROCALCINOSIS

  • Most common crystalline arthropathy

    Types: 1. Osteoarthritic form (35 60%)
    2. Pseudogout = acute synovitis (10 20%)
    3. Rheumatoid form (2 6%)
    4. Pseudoneuropathic arthropathy (2%)
    5. Asymptomatic with tophaceous pseudogout (common)
    Associated with: hyperparathyroidism, hypothyroidism, hemochromatosis, hypomagnesemia
    Prevalence: widespread in older population; M:F = 3:2

  • calcium pyrophosphate crystals in synovial fluid + within leukocytes (characteristic weakly positive birefringent diffraction pattern)

  • acute / subacute / chronic joint inflammation

    Location: (a) knee (especially meniscus + cartilage of patellofemoral joint)
    (b) wrist (triangular fibrocartilage in distal radioulnar joint bilaterally)
    (c) pelvis (sacroiliac joint, symphysis)
    (d) spine (annulus fibrosis of lumbar intervertebral disk; NEVER in nucleus pulposus as in ochronosis)
    (e) shoulder (glenoid), hip (labrum), elbow, ankle, acromioclavicular joint

  • polyarticular chondrocalcinosis (in fibro- and hyaline cartilage)

  • large subchondral cyst (HALLMARK)

  • numerous intraarticular bodies (fragmentation of subchondral bone)

  • involvement of tendons, bursae, pinnae of the ear

    N.B.: pyrophosphate arthropathy resembles osteoarthritis: joint space narrowing + extensive subchondral sclerosis

  • @ Hand

    Distribution: radiocarpal compartment; trapezioscaphoid joint + 1 CMC; 2,3 MCP joints; bilateral symmetric

    • resembling degenerative joint disease (without DIP and PIP involvement)

    • small hook-like osteophytes at radial aspect of metacarpal heads 2 & 3

    • extensive narrowing / obliteration of joint space between distal radius + scaphoid:

      • incorporation of scaphoid into articular surface of radius

      • prominent cysts

    • calcification of triangular fibrocartilage

    • scapholunate separation

    • destruction of trapezioscaphoid space

  • @ Knee

    • medial femorotibial + patellofemoral compartments commonly involved simultaneously (as in osteoarthritis) but with greater osseous destruction + fragmentation

    • disproportionate narrowing of patellofemoral joint

  • @ Spine

    • chondrocalcinosis / calcifications of outer fibers of annulus fibrosus resembling syndesmophytes

    • vertical radiodense line in symphysis pubis

Camptomelic Dysplasia

= sporadic / autosomal recessive dwarfism

Incidence: 0.05:10,000 births

Associated with:

  • Hydrocephalus (23%)

  • Congenital heart disease (30%): VSD, ASD, tetralogy, AS

  • Hydronephrosis (30%)

  • npretibial dimple

  • macrocephaly, cleft palate, micrognathia (90 99%)

  • @ Chest & spine

    • hypoplastic scapulae (92%)

    • narrow bell-shaped chest

    • hypoplastic vertebral bodies + nonmineralized pedicles (especially lower cervical spine)

  • @ Pelvis

    • vertically narrowed iliac bones

    • vertical inclination of ischii

    • wide symphysis

    • narrow iliac bones with small wings

    • shallow acetabulum

  • @ Extremities (lower extremity more severely affected)

    • dislocation of hips + knees

    • anterior bowing (= campto) of long bones: marked in tibia + moderate in femur

    • hypoplastic fibula

    • small secondary ossification center of knee

    • small primary ossification center of talus

    • clubfoot

  • OB-US:

    • bowing of tibia + femur

    • decreased thoracic circumference

    • hypoplastic scapulae

    • cleft palate

Prognosis: death usually <5 months of age (within first year in 97%) due to respiratory insufficiency

Carpal Tunnel Syndrome

= entrapment syndrome caused by chronic pressure on the median nerve within the carpal tunnel

Cause: repetitive wrist / finger flexion; carpal tunnel crowding by cyst / mass / flexor tendon tendinitis or tenosynovitis / anomalous origin of lumbrical muscles
Pathogenesis: probably ischemia with venous congestion (stage 1), nerve edema from anoxic damage to capillary endothelium (stage 2), impairment of venous + arterial blood supply (stage 3)

P.56


  • nocturnal hand discomfort

  • weakness, clumsiness, finger paresthesias

    MR:

    • pseudoneuroma of median nerve = swelling of median nerve proximal to carpal tunnel

    • swelling of nerve within carpal tunnel

    • increased signal intensity of nerve on T2WI

    • volar bowing of flexor retinaculum

    • swelling of tendon sheath (due to tenosynovitis)

    • mass(es) within carpal tunnel

    • marked enhancement (nerve edema = breakdown of blood-nerve barrier)

    • no enhancement (ischemia) provoked by wrist held in an extended / flexed position

Carpenter Syndrome

  • = ACROCEPHALOPOLYSYNDACTYLY type 2

  • autosomal recessive

  • retardation

  • hypogonadism

  • patent ductus arteriosus

  • acro(oxy)cephaly

  • preaxial polysyndactyly + soft-tissue syndactyly

Cerebrocostomandibular Syndrome

  • = rare bone disorder of uncertain transmission

  • respiratory distress (due to flail chest + airway abnormalities)

  • 11 pairs of ribs:

    • abnormal costovertebral articulations

    • posterior ossification gaps resembling fractures

  • microcephaly

  • micrognathia

  • congenital heart disease

    DDx: multiple fractures

Chondroblastoma

= CODMAN TUMOR = BENIGN CHONDROBLASTOMA = CARTILAGE-CONTAINING GIANT CELL TUMOR

Incidence: 1% of primary bone neoplasms (700 cases in world literature)
Age: peak in 2nd decade (range of 8 59 years); 10 26 years (90%); M:F = 2:1; occurs before cessation of enchondral bone growth
Path: derived from primitive cartilage cells
Histo: polyhedral chondroblasts + multinucleated giant cells + nodules of pink amorphous material
(= chondroid) = epiphyseal chondromatous giant cell tumor (resembles chondromyxoid fibroma); chicken wire calcification = pericellular deposition of calcification is virtually PATHOGNOMONIC

  • symptomatic for months to years prior to treatment

  • mild joint pain, tenderness, swelling (joint effusion)

  • limitation of motion

Location:

  • long bones (80%): proximal femur + greater trochanter (23%), distal femur (20%), proximal tibia (17%), proximal humerus (17%)

    • 2/3 in lower extremity, 50% about knee

    • may occur in apophyses (minor + greater trochanter, patella, greater tuberosity of humerus)

  • flat bones: near triradiate cartilage of innominate bone, rib (3%)

  • short tubular bones of hand + feet

Site: eccentric medullary, subarticular location with open growth plate (98% begin within epiphysis); tumor growth may continue to involve metaphysis (50%) + rarely diaphysis

  • oval / round eccentrically placed lytic lesion of epiphysis

  • 1 4 cm in diameter occupying < one-half of epiphysis

  • well-defined sclerotic margin, lobulated in 50%

  • stippled / irregular calcifications in 25 30 50% (cartilaginous clumps better visualized by CT)

  • intact scalloped cortical border

  • thick periosteal reaction in metaphysis (50%) / joint involvement

  • periostitis of adjacent metaphysis / diaphysis (30 50%)

  • open growth plate in majority of patients

MR:

  • MR tends to overestimate extent + aggressiveness due to large area of reactive edema!

  • intermediate to low signal intensity on T2WI relative to fat

  • extensive intramedullary signal abnormalities consistent with bone marrow edema

  • peripheral rim of very low signal intensity

  • hypointense changes on T1WI + hyperintense on T2WI in adjacent soft tissues (muscle edema) in 50%

  • joint effusion

Prognosis: almost always benign; may become locally aggressive; rarely metastasizes
Dx: surgical biopsy
Rx: curettage + bone chip grafting (recurrence in 25%)
DDx: (1) Ischemic necrosis of femoral head (may be indistinguishable, more irregular configuration)
(2) Giant cell tumor (usually larger + less well demarcated, not calcified, older age group with closed growth plate)
(3) Chondromyxoid fibroma
(4) Enchondroma
(5) Osteomyelitis (less well-defined, variable margins)
(6) Aneurysmal bone cyst
(7) Intraosseous ganglion
(8) Langerhans cell histiocytosis (less well-defined, variable margins)
(9) Primary bone sarcoma

Chondrodysplasia Punctata

  • = CONGENITAL STIPPLED EPIPHYSES = DYSPLASIA EPIPHYSEALIS PUNCTATA = CHONDRODYSTROPHIA CALCIFICANS CONGENITA

  • = proportional / mesomelic dwarfism

    Etiology: peroxisomal disorder characterized by fibroblast plasmalogen deficiency
    Incidence: 1:110,000 births

  • AUTOSOMAL RECESSIVE CHONDRODYSPLASIA PUNCTATA = RHIZOMELIC TYPE

    Associated with: CHD (common)

    • flat face

    • congenital cataracts

    • ichthyotic skin thickening

    • mental retardation

      • P.57


    • cleft palate

    • multiple small punctate calcifications of varying size in epiphyses (knee, hip, shoulder, wrist), in base of skull, in posterior elements of vertebrae, in respiratory cartilage and soft tissues (neck, rib ends) before appearance of ossification centers

    • prominent symmetrical shortening of femur + humerus (rarely all limbs symmetrically affected)

    • congenital dislocation of hip

    • flexion contractures of extremities

    • clubfeet

    • metaphyseal splaying of proximal tubular bones (in particular about knee)

    • thickening of diaphyses

    • prominent vertebral + paravertebral calcifications

    • coronal clefts in vertebral bodies

      Prognosis: death usually <1 year of age
      DDx: Zellweger syndrome

  • CONRADI-H NERMANN DISEASE

    • = NONRHIZOMELIC TYPE

    • more common milder nonlethal variety;

    • autosomal dominant

    • normal intelligence

    • more widespread but milder involvement as above

      Prognosis: survival often into adulthood
Cx: respiratory failure (severe underdevelopment of ribs), tracheal stenosis, spinal cord compression
DDx: (1) Cretinism (may show epiphyseal fragmentation, much larger calcifications within epiphysis)
(2) Warfarin embryopathy
(3) Zellweger syndrome

Chondroectodermal Dysplasia

  • = ELLIS-VAN CREVELD SYNDROME = MESODERMAL DYSPLASIA

  • = autosomal recessive acromesomelic dwarfism

    Incidence: 120 cases; in inbred Amish communities
    Associated with: congenital heart disease in 50% (single atrium, ASD, VSD)

  • ectodermal dysplasia:

    • absent / hypoplastic brittle spoon-shaped nails

    • irregular + pointed dysplastic teeth, partial anodontia, teeth may be present at birth

    • scant / fine hair

  • obliteration of maxillary mucobuccal space (thick frenula between alveolar mucosa + upper lip)

  • strabismus

  • genital malformations: epispadia, hypospadia, hypoplastic external genitalia, undescended testicles

  • hepatosplenomegaly

  • accelerated skeletal maturation

  • normal spine

  • @ Skull

    • wormian bones

    • cleft lip

  • @ Chest

    • elongated narrow thorax in AP + transverse dimensions exaggerating the heart size

    • cardiomegaly (frequently ASD / single atrium)

    • short horizontal ribs + anterior osseous expansion

    • elevated clavicles

  • @ Pelvis

    • small flattened ilium

    • trident shape of acetabulum with indentation in roof + bony spur (almost pathognomonic)

    • acetabular + tibial exostoses

  • @ Extremities

    • variety of micromelia (= thickening + shortening of all long bones):

      • acromelia = hypoplasia / absence of terminal phalanges

      • mesomelia = shortening of forearms + lower legs (radius + tibia > humerus + femur)

    • cone-shaped epiphyses

    • premature ossification of proximal humeral + femoral epiphyses

    • @ Upper extremity

      • drumstick forearm = swelling of proximal end of ulna + distal end of radius

      • anterior dislocation of radial head (due to shortening of ulna)

      • carpal / tarsal fusion = frequent fusion of two / more carpal (hamate + capitate) + tarsal bones (after complete ossification)

      • supernumerary carpal bones

      • postaxial polydactyly common (usually finger, rarely toe) syndactyly of hands + feet

    • @ Lower extremity

      • genu valgum:

        • slanting of proximal tibial metaphysis (= delayed development of tibial plateau)

        • excessive shortening of fibula

      • widening of proximal tibial shaft

      • medial tibial diaphyseal exostosis

  • OB-US:

    • proportional shortening of long bones

    • small thorax with decreased circumference

    • increased cardiothoracic ratio

    • ASD

    • polydactyly

    Prognosis: death within first month of life in 33 50% (due to respiratory / cardiac complications)
    DDx: asphyxiating thoracic dysplasia (difficult distinction); rhizomelic achondroplasia

Chondromalacia Patellae

  • = pathologic softening of patellar cartilage leading to defects of surface (chondrosis) / osteoarthritis

    Cause: trauma, tracking abnormality of patella

  • anterior knee pain

  • asymptomatic (incidental arthroscopic diagnosis)

Chondromyxoid Fibroma

Rare benign cartilaginous tumor; initially arising in cortex

Incidence: <1% of all bone tumors
Histo: chondroid + fibrous + myxoid tissue (related to chondroblastoma); may be mistaken for chondrosarcoma
Age: peak 2nd 3rd decade (range of 5 79 years); M:F = 1:1

  • slowly progressive local pain, swelling, restriction of motion

    P.58


    Classification of Chondromalacia Patellae

    Grade Arthroscopic Pathology T1WI of MRI
    1 softening + swelling of articular cartilage (chondrosis) focal hypointense areas not extending to cartilage surface / subchondral bone (MR / MR arthrography unreliable)
    2 blistering of articular cartilage producing deformity of surface <1 cm in diameter focal hypointense areas extending to cartilage surface with preservation of sharp cartilage margins
    3 surface irregularity + cartilage fibrillation with minimal extension to subchondral bone >1 cm in diameter focal hypointense areas extending to articular surface but not to osseous surface; loss of sharp dark margin between articular cartilage of patella + trochlea
    4 ulceration with exposure of subchondral bone focal hypointense areas extending from subchondral bone to cartilage surface; cartilage thinned to subchondral bone
    Location: (a) long bones (60%): about knee (50%), proximal tibia (82% of tibial lesions), distal femur (71% of femoral lesions), fibula
    (b) short tubular bones of hand + feet (20%)
    (c) flat bones: pelvis, ribs (classic but uncommon)
    Site: eccentric, metaphyseal (47 53%), metadiaphyseal (20 43%), metaepiphyseal (26%), diaphyseal (1 10%), epiphyseal (3%)

  • expansile ovoid lesion with radiolucent center + oval shape at each end of lesion

  • long axis parallel to long axis of host bone (1 10 cm in length and 4 7 cm in width)

  • geographic bone destruction (100%)

  • well-defined sclerotic margin (86%)

  • expanded shell = bulged + thinned overlying cortex (68%)

  • partial cortical erosion (68%)

  • scalloped margin (58%)

  • septations (57%) may mimic trabeculations

  • stippled calcifications within tumor in advanced lesions (7%)

  • NO periosteal reaction (unless fractured)

    Prognosis: 25% recurrence rate following curettage
    Cx: malignant degeneration distinctly unusual
    DDx: (1) Aneurysmal bone cyst
    (2) Simple bone cyst
    (3) Nonossifying fibroma
    (4) Fibrous dysplasia
    (5) Enchondroma
    (6) Chondroblastoma
    (7) Eosinophilic granuloma
    (8) Fibrous cortical defect
    (9) Giant cell tumor

Chondrosarcoma

  • PRIMARY CHONDROSARCOMA

    • no preexisting bone lesion

  • SECONDARY CHONDROSARCOMA

    as a complication of a preexisting skeletal abnormality such as

    • Osteochondroma

    • Enchondroma

    • Parosteal chondroma

Spread: via marrow cavity / periosteum
Metastases (uncommon) to: lung, epidural space

CT:

  • chondroid matrix mineralization of rings and arcs (CHARACTERISTIC) in 70%

  • nonmineralized portion of tumor hypodense to muscle (high water content of hyaline cartilage)

  • extension into soft-tissues

MR:

  • low to intermediate signal intensity on T1WI

  • high signal intensity on T2WI + hypointense areas (due to mineralization / fibrous septa)

  • enhancement of fibrous septations

Central Chondrosarcoma

  • = INTRAMEDULLARY CHONDROSARCOMA = ENDOSTEAL CHONDROSARCOMA

    Incidence: 3rd most common primary bone tumor (1st multiple myeloma, 2nd osteosarcoma); 8 17% of biopsied primary bone tumors
    Path: lobular morphology with variable amounts of calcium; presence of fibrous bands at tumor-marrow interface suggests malignancy (DDx from atypical enchondroma)
    Histo: arises from chondroblasts (tumor osteoid is never formed)
    Age: median 45 years; 50% >40 years; 10% in children (rapidly fatal); M:F = 2:1

  • hyperglycemia as paraneoplastic syndrome (85%)

    Location: neck of femur, pubic rami, proximal humerus, ribs (19%), skull (sphenoid bone, cerebellopontine angle, mandible), sternum, spine (3 12%)
    Site: central within medullary canal + meta- / diaphysis

  • expansile osteolytic lesion 1 to several cm in size

  • short transition zone sclerotic margin (well defined from host bone)

  • small irregular punctate / snowflake type of calcification; single / multiple

  • late: loss of definition + break through cortex

  • endosteal cortical thickening, sometimes at a distance from the tumor (due to invasion of haversian system)

  • presence of large soft-tissue mass

    DDx: benign enchondroma, osteochondroma, osteosarcoma, fibrosarcoma

Peripheral Chondrosarcoma

  • = EXOSTOTIC CHONDROSARCOMA

  • = malignant degeneration of hereditary multiple osteochondromatosis and rarely of a solitary exostosis (beginning in cartilaginous cap of exostosis)

    P.59


    Frequency: 8% of all chondrosarcomas
    Average age: 50 55 years for solitary exostosis; 25 30 years for hereditary multiple osteochondromatosis; M:F = 1.5:1
    Histo: low histologic grade in 67 85%

  • growth after skeletal maturity

  • gradually increasing pain, often worse at night

  • local swelling / palpable mass (45%)

    Location: pelvis, hip, scapula, sternum, ribs, ends of humerus / femur, skull, facial bones

  • growth of a previously unchanged osteochondroma in a skeletally mature patient

  • unusually large soft-tissue mass (= hyaline cartilage cap) containing flocculent / streaky chondroid calcifications (CHARACTERISTIC):

    • cartilage cap 1.5 12 cm (average, 5.5 6 cm) thick

      • >1.5 cm is suspect of malignant transformation

  • irregular / indistinct lesion surface:

    • dense radiopaque center with streaks radiating to periphery with loss of smooth margin

    focal regions of radiolucency in interior of lesion

  • erosion / destruction of adjacent bone

    Metastases: in 3 7%, most commonly to lung
    Rx: wide resection
    Prognosis: 70 90% long-term survival
    DDx: (1) Osteochondroma (densely calcified with multiple punctate calcifications)
    (2) Parosteal osteosarcoma (more homogeneous density of calcified osteoid)

Clear Cell Chondrosarcoma

  • Usually mistaken for chondroblastoma because of low grade malignancy (may be related)!

Histo: small lobules of tissue composed of cells with centrally filled vesicular nuclei surrounded by large clear cytoplasm
Age: 19 68 years, predominantly after epiphyseal fusion
Location: proximal femur, proximal humerus, proximal ulna, lamina vertebrae (5%); pubic ramus
Site: epiphysis

Enchondroma versus Chondrosarcoma in Appendicular Skeleton

  Enchondroma Intramedullary Chondrosarcoma
Mean age and sex 40 years; M:F = 2:3 50 years; M:F = 11:9
Palpable mass 28% 82%
Pain 40% (fracture associated) 95% (longer duration + increasing severity)
Lesion location hands, feet axial skeleton (spine, pelvis)
Site diaphysis metaphysis, epiphysis
Lesion size <5 cm >5 6 cm
Endosteal scalloping    
   relative to cortical thickness 90% <2/3 of cortical thickness 90% >2/3 of cortical thickness,
   relative to lesion length 66% along <2/3 of lesion 79% along >2/3 of lesion
Cortical remodeling (radiography) 15% 47%
Cortical thickening (radiography) 17% 47%
Periosteal reaction (radiography) 3% 47%
Pathologic fracture (radiography) 5% 27%
Matrix mineralization (CT) 100% (more extensive) 94% (less extensive)
Cortical destruction (CT) 8% 88%
Soft-tissue extension (MR) 3% 76%
Small hyperintense foci (T1WI) 65% 35%

  • single lobulated oval / round sharply marginated lesion of 1 2 cm in size

  • surrounding increased bone density

  • aggressive rapid growth over 3 cm

  • may contain calcifications

  • bone often enlarged

  • indistinguishable from conventional chondrosarcoma / chondroblastoma (slow growth over years)

Extraskeletal Chondrosarcoma

Incidence: 2% of all soft-tissue sarcomas

Myxoid Extraskeletal Chondrosarcoma

(most common)

Mean age: 50 years (range 4 92 years); M > F
Histo: surrounded by fibrous capsule + divided into multiple lobules by fibrous septa; delicate strands of small elongated chondroblasts are suspended in an abundant myxoid matrix; foci of mature hyaline cartilage are rare

  • slowly growing soft-tissue mass

  • pain + tenderness (33%)

  • Metastatic in 40 45% at time of presentation!

    Location: extremities (thigh most common)
    Site: deep soft tissues; subcutis (25%)

  • lobulated soft-tissue mass WITHOUT calcification / ossification

  • usually between 4 and 7 cm in diameter

MR:

  • approximately equal to muscle on T1WI + equal to fat on T2WI

  • may mimic a cyst / myxoma

P.60


Prognosis: 45% 10-year survival rate; 5 15 years survival after development of metastases

Extraskeletal Mesenchymal Chondrosarcoma

  • 50% of all mesenchymal chondrosarcomas arise in soft tissues

    Histo: proliferation of small primitive mesenchymal cells with scattered islands of cartilage; hemangiopericytoma-like vascular pattern
    Bimodal age distribution: M = F

    • tumors of head + neck in 3rd decade (common): meninges, periorbital region

    • tumors of thigh + trunk in 5th decade

  • frequently metastasized to lungs + lymph nodes

  • matrix mineralization (50 100%) characterized as rings + arcs / flocculent + stippled calcification / dense mineralization

MR:

  • approximately equal to muscle on T1WI + equal to fat on T2WI

  • signal voids from calcifications

  • homogeneous enhancement

Prognosis: 25% 10-year survival rate

Cleidocranial Dysostosis

  • = CLEIDOCRANIAL DYSPLASIA = MUTATIONAL DYSOSTOSIS

  • = delayed ossification of midline structures (particularly of membranous bone)

  • Autosomal dominant disease

  • @ Skull

    • large head

    • diminished / absent ossification of skull (in early infancy)

    • wormian bones

    • widened fontanels + sutures with delayed closure

    • persistent metopic suture

    • brachycephaly + prominent bossing

    • large mandible

    • high narrow palate ( cleft)

    • hypoplastic paranasal sinuses

    • delayed / defective dentition

  • @ Chest

    • hypoplasia / absence (10%) of clavicles (defective development usually of lateral portion, R > L (DDx: congenital pseudarthrosis of clavicle)

    • thorax may be narrowed + bell-shaped

    • supernumerary ribs

    • incompletely ossified sternum

    • hemivertebrae, spondylosis (frequent)

  • @ Pelvis

    • delayed ossification of bones forming symphysis pubis (DDx: bladder exstrophy)

    • hypoplastic iliac bones

  • @ Extremities

    • radius short / absent

    • elongated second metacarpals

    • pseudoepiphyses of metacarpal bases

    • short hypoplastic distal phalanges of hand

    • pointed terminal tufts

    • coned epiphyses

    • coxa vara = deformed / absent femoral necks

    • accessory epiphyses in hands + feet (common)

OB-US:

  • cephalopelvic disproportion (large fetal head + narrow birth canal of affected maternal pelvis) necessitates cesarean section

Coccidioidomycosis

Histo: chronic granulomatous process in bones, joints, periarticular structures
Location: (a) bones: most frequently in metaphyses of long bones + medial end of clavicle, spine, ribs, pelvis / bony prominences of patella, tibial tuberosity, calcaneus, olecranon, acromion
(b) weight-bearing joints (33%): ankle, knee, wrist, elbow
    desert rheumatism = immune-complex mediated arthritis
(c) tenosynovitis of hand, bursitis

  • focal areas of destruction, formation of cavities (early) = bubbly bone lesion

  • bone sclerosis surrounding osteolysis (later, rare)

  • proliferation of overlying periosteum

  • destruction of vertebra with preservation of disk space

  • psoas abscess indistinguishable from tuberculosis, may calcify

  • joints rarely infected (usually monoarticular from direct extension of osteomyelitic focus): synovial effusion, osteopenia, joint space narrowing, bone destruction, ankylosis

  • soft-tissue abscesses common

    DDx: tuberculosis

Congenital Insensitivity to Pain With Anhydrosis

  • = rare autosomal recessive disorder presumably on the basis of abnormal neural crest development

    Age: presenting at birth
    Incidence: 15 reported cases
    Path: absence of dorsal + sympathetic ganglia, deficiency of neural fibers <6 m in diameter + disproportionate number of fibers of 6 10 m in diameter

  • history of painless injuries + burns (DDx: familial dysautonomia, congenital sensory neuropathy, hereditary sensory radicular neuropathy, acquired sensory neuropathy, syringomyelia)

  • abnormal pain + temperature perception

  • burns, bruises, infections are common

  • biting injuries of fingers, lips, tongue

  • absence of sweating

  • mental retardation

    CRITERIA: (1) defect must be present at birth
    (2) general insensitivity to pain
    (3) general mental / physical retardation

  • epiphyseal separation in infancy (epiphyseal injuries result in growth problems)

  • metaphyseal fractures in early childhood

  • diaphyseal fractures in late childhood

  • Charcot joints = neurotrophic joints (usually weight-bearing joints) with effusions + synovial thickening

  • ligamentous laxity

  • bizarre deformities + gross displacement + considerable hemorrhage (unnoticed fractures + dislocations)

    • P.61


  • osteomyelitis + septic arthritis may occur + progress extensively

    DDx: (1) sensory neuropathies (eg, diabetes mellitus)
    (2) hysteria
    (3) syphilis
    (4) mental deficiency,
    (5) syringomyelia
    (6) organic brain disease

Cornelia De Lange Syndrome

  • = AMSTERDAM DWARFISM

  • mental retardation (IQ <50)

  • hirsutism; hypoplastic genitalia

  • feeble growling cry

  • high forehead; short neck

  • arched palate

  • bushy eyebrows meeting in midline + long curved eyelashes

  • small nose with depressed bridge; upward tilted nostrils; excessive distance between nose + upper lip

  • small + brachycephalic skull

  • hypoplasia of long bones (upper extremity more involved)

  • forearm bones may be absent

  • short radius + elbow dislocation

  • thumbs placed proximally (hypoplastic 1st metacarpal)

  • short phalanges + clinodactyly of 5th finger

Cortical Desmoid

  • = AVULSIVE CORTICAL IRREGULARITY = PERIOSTEAL / SUBPERIOSTEAL DESMOID = SUBPERIOSTEAL / CORTICAL ABRASION = SUBPERIOSTEAL CORTICAL DEFECT

  • = rare fibrous lesion of the periosteum

    Age: peak 14 16 years (range of 3 17 years); M:F = 3:1
    Histo: shallow defect filled with proliferating fibroblasts, multiple small fragments of resorbing bone (microavulsions) at tendinous insertions

  • no localizing signs / symptoms

    Location: posteromedial aspect of medial femoral epicondyle along medial ridge of linea aspera at attachment of adductor magnus aponeurosis; 1/3 bilateral

  • area of cortical thickening

  • 1 2 cm irregular, shallow, concave saucerlike crater with sharp margin

  • lamellated periosteal reaction

  • localized cortical hyperostosis proximally (healing phase)

  • May be confused with a malignant tumor (eg, osteosarcoma) / osteomyelitis!

Cri-Du-Chat Syndrome

  • = deletion of short arm of 5th chromosome (5 p)

  • generalized dwarfism due to marked growth retardation

  • failure to thrive

  • peculiar high-pitched cat cry (hypoplastic larynx)

  • antimongoloid palpebral fissures

  • strabismus

  • profound mental retardation

  • round facies

  • low-set ears

    Associated with: congenital heart disease (obtain CXR!)

  • agenesis of corpus callosum

  • microcephaly

  • hypertelorism

  • small mandible

  • faulty long-bone development

  • short 3rd, 4th, 5th metacarpals

  • long 2nd, 3rd, 4th, 5th proximal phalanges

  • horseshoe kidney

    Dx: made clinically

Crouzon Syndrome

  • = CRANIOFACIAL SYNOSTOSIS / DYSOSTOSIS

  • = Apert syndrome without syndactyly

  • = skull + cranial base deformities characterized by craniosynostosis, maxillary hypoplasia, shallow orbits, ocular proptosis, bifid uvula, cleft palate

    Prevalence: 1:25,000
    Etiology: autosomal dominant inheritance (in 67%)
    Associated intracranial anomalies: anomalous venous drainage, hydrocephalus (often progressive), Chiari I malformation (71%)

  • parrot-beak nose

  • strabismus

  • deafness

  • mental retardation

  • dental abnormalities

  • bifid uvula

  • acanthosis nigrans (= hyperpigmented hyperkeratotic lesions on neck + near joint flexures)

  • premature craniosynostosis: acro(oxy)cephaly / brachycephaly / scaphocephaly / trigonocephaly / cloverleaf skull

  • hypertelorism + exophthalmos (due to shallow orbits)

  • hypoplastic maxilla (relative prominence of mandible)

  • cleft palate

  • calcification of stylohyoid ligament (in 50% of patients >4 years of age)

  • C2 to C5 spine abnormalities (in up to 40%)

  • elbow malformation (18%)

  • minor hand deformities (10%)

  • visceral anomalies (7%)

  • musculoskeletal deformities (7%)

OB-US:

  • cloverleaf appearance (coronal view) + bilateral frontal indentations (axial view) of skull

  • increased interorbital distance + ocular proptosis

  • mild ventriculomegaly

Cruciate Ligament Injury

  • COMPLETE TEAR

    • failure to identify ligament

    • amorphous areas of high signal intensity on T1WI + T2WI with inability to define ligamentous fibers

    • focal discrete complete disruption of all visible fibers

  • PARTIAL / INTRASUBSTANCE TEAR

    • abnormal signal intensity within substance of ligament with some intact + some discontinuous fibers

Anterior Cruciate Ligament Injury (ACL tear)

Frequency: in up to 69% of all patients undergoing arthroscopy; in up to 72% of acutely injured knees with hemarthrosis
Mechanism: twisting, valgus impaction + internal rotation, hyperextension of knee with foot planted (football) / lower leg forcibly externally rotated during knee flexion (backwards fall while skiing)

  • pivot shift test (82 90% sensitive) = examiner applies valgus stress on internally rotated leg while flexing the knee; induced anterolateral rotary subluxation reduces spontaneously at 40 flexion with an audible pop

  • anterior drawer sign (22 80% sensitive) = proximal tibia displaces anteriorly with the knee flexed at 60 90

  • Lachman test (77 99% sensitive) = same as anterior drawer sign with knee flexed at 10 20

    Location: midsubstance of ligament / near femoral attachment (in adults) / avulsion of anterior intercondylar eminence or tibial spines (in children)

  • If the ACL appears intact in one of the sagittal oblique sequences discordant findings in other sequences can be disregarded!

    Site: intrasubstance tear near insertion of femoral condyle (frequently); bone avulsion (rarely)

  • loss of fiber continuity + abnormal fiber orientation on PD image

  • hyperintense signal (= focal fluid collection / soft-tissue edema) replacing the tendon substance in acute tear on T2WI

  • pseudomass (hematoma + torn fibers) in intercondylar notch near femoral attachment

  • concavity of anterior margin of ligament

  • nondisplaced avulsion fracture of tibial eminence in children (coronal T1WI)

Secondary signs (low sensitivity, high specificity):

  • anterior translation of tibia (= anterior drawer sign) by >5 mm with respect to femur measured at midsagittal plane of lateral femoral condyle

  • uncovering of lateral meniscus = posterior displacement of posterior horn of lateral meniscus >3.5 mm behind tibial plateau

  • bowed PCL due to increased laxity = angle between proximal + distal limbs of PCL <105

Associated signs:

  • for anterolateral rotary instability (football, skiing):

    • bone bruise in lateral compartment (posterolateral tibia + terminal sulcus of lateral femoral condyle) in 40 90% on fat-suppressed T2WI

      • ACL intact in 28% of adolescents with bone bruise

    • low-signal intensity line surrounded by region of high-signal intensity marrow edema in posterior aspect of lateral tibial plateau (= occult fracture) on STIR image

  • for hyperextension injury:

    • bone contusion in anterior tibial plateau + femoral condyles

  • varus stress with external rotation:

    • avulsion of joint capsule from lateral tibial rim (Segond fracture)

  • deepening of lateral femoral sulcus >1.5 mm (due to osteochondral impaction injury)

False-positive Dx:

  • slice thickness / interslice gap too great

  • adjacent fluid / synovial proliferation

  • cruciate ganglion / synovial cyst

Associated injuries:

  • meniscal tear (lateral > medial) in 65%

Rx: (1) conservative: strengthening of quadriceps muscle + brace for activities
(2) arthroscopic reconstruction with autograft (patellar tendon / combined semitendinosus and gracilis tendon) or allograft (cadaveric patellar / Achilles tendon)

Subacute ACL Tear

Definition: few weeks after injury

  • fibers better defined as hemorrhage + edema subside

  • change in fiber contour + angle of residual fragments

Chronic ACL Tear

Definition: months to years after injury

  • bridging fibrous scar within intercondylar notch (simulating an intact ligament with its low signal intensity)

  • disorganized scar tissue instead of linear parallel fibers

  • major distal ACL fragment assumes a more horizontal orientation (= less steep than the roof of the intercondylar notch or Blumensaat line)

  • ACL may fuse to posterior cruciate ligament

  • complete absence of ligament

Partial ACL Tear (15%)

  • Extremely difficult to diagnose! 40 50% of partial tears are missed on MR!

  • positive Lachman test (in 12 30%)

  • MR primary signs positive for injury (in 33 43%)

Posterior Cruciate Ligament Injury (PCL)

Prevalence: 2 23% of all knee injuries

  • midsubstance of PCL most frequently involved (best seen on sagittal images)

  • bone avulsion from posterior tibial insertion (<10%), best seen on lateral plain film

Mechanism:

  • Direct blow to proximal anterior tibia with knee flexed (dashboard injury)

    • midsubstance PCL tear

    • injury to posterior joint capsule

    • bone contusion at anterior tibial plateau + femoral condyles farther posteriorly

  • Hyperextension of knee

    • avulsion of tibial attachment of PCL (with preservation of PCL substance)

    • ACL rupture

    • bone contusion in anterior tibial plateau + anterior aspect of femoral condyles

  • Severe ab- / adduction + rotational forces

    • + injury to collateral ligaments

    Associated with: coexistent ligamentous injury in 70%
    anterior cruciate ligament 27 38%
    medial collateral ligament 20 23%
    lateral collateral ligament 6 7%
    medial meniscal tear 32 35%
    lateral meniscal tear 28 30%
    bone marrow injury 35 36%
    effusion 64 65%

  • In 30% of cases injury of PCL is isolated!

  • posterior tibial laxity

  • difficult to evaluate arthroscopically unless ACL torn

Deep Fibromatosis

Aggressive Infantile Fibromatosis

  • = childhood equivalent of deep fibromatosis

    Age: first 2 years of life; rarely >5 years of age; M > F
    Histo: may mimic infantile fibrosarcoma

  • firm nodular soft-tissue mass within skeletal muscle / fascia / periosteum

Location: head, neck (tongue, mandible, mastoid), shoulder, thigh, foot

Extraabdominal Desmoid Tumor

  • = AGGRESSIVE FIBROMATOSIS = DEEP FIBROMATOSIS = MUSCULOAPONEUROTIC FIBROMATOSIS

  • = common benign aggressively growing soft-tissue tumor arising from connective tissue of muscle, fascia, aponeurosis outside abdominal cavity

Peak age: 25 35 years
Histo: parallel halo arrays of uniform-appearing fibroblasts surrounded by highly variable amounts of collagen fibers with infiltrative growth pattern

  • painless soft-tissue mass

    Location: extremities (70%); shoulder (20%), chest wall + back (15%), thigh (12%), mesentery (10%), neck (10%), knee (7%); solitary (majority) / synchronous multicentricity in same extremity (10 15%)

  • Most common benign soft-tissue tumor of the foot

    Site: fascia in / around muscle

  • mostly <10 cm in diameter

  • @ Bone

    • Erlenmeyer flask deformity in multicentric fibromatosis (infrequent)

  • @ Abdominal wall

    Prevalence: in 87% in females of childbearing age
    Predilection: female patients taking birth control pills / during or after pregnancy
    Location: aponeurosis of rectus abdominis, internal oblique muscle

MR:

  • poorly defined (with invasion of fat / muscle) / lobulated well-defined lesion

  • hypo- / isointense to muscle on T1WI

  • hyperintense (hypercellular) / hyperintense with areas of low intensity (intermixed with fibrous components) / hypointense (hypocellular) on T2WI

Cx: compresses / engulfs adjacent structures
Prognosis: 75% recurrence within 2 years after surgical excision (up to 87% local recurrence in <30 years of age; 20% recurrence rate in >20 years of age)

Abdominal Desmoid Tumor

  • = DESMOID TUMOR

  • = uncommon benign tumor of the subgroup of fibromatoses consisting of fibrous tissue with insidious growth [desmos, Greek = band / tendon]

Location: mesentery (most common mesenteric primary), musculoaponeurosis of rectus, internal oblique muscle; occasionally external oblique muscle
Age: peak age in 3rd decade, 70% between 20 and 40 years of age; M:F = 1:3
Path: poorly circumscribed coarsely trabeculated tumor resembling scar tissue, confined to musculature + overlying aponeurosis
Histo: elongated spindle-shaped cells of uniform appearance, septated by dense bands of collagen, infiltration of adjacent tissue (DDx: low-grade fibrosarcoma, reactive fibrosis)
Associated with: Gardner syndrome, multiple pregnancies, prior trauma

firm slowly growing deep-seated mass

Size: 5 20 cm in diameter

MR:

  • hypointense to muscle on T1WI + variable intensity on T2WI

CT:

  • ill-defined / well-circumscribed mass

  • usually higher attenuation than muscle

  • enhancement

  • retraction, angulation, distortion of small / large bowel with mesenteric infiltration

US:

  • sharply defined + smoothly marginated mass of low / medium / high echogenicity

Cx: compression / displacement of bowel / ureter, intestinal perforation
Prognosis: locally aggressive growth; 25 65% recurrence rate
Rx: local resection + radiotherapy, antiestrogen therapy
DDx: (1) Malignant tumor: metastasis, fibrosarcoma, rhabdomyosarcoma, synoviosarcoma, liposarcoma, fibrous histiocytoma, lymphoma
(2) Benign tumor: neurofibroma, neuroma, leiomyoma
(3) Acute hematoma

Infantile Myofibromatosis

  • = GENERALIZED HAMARTOMATOSIS = CONGENITAL MULTIPLE FIBROMATOSIS = MULTIPLE VASCULAR LEIOMYOMAS = DESMOFIBROMATOSIS

  • = rare disorder characterized by proliferation of fibroblasts

P.62


P.63


Cause: unknown
Frequency: most common fibromatosis in childhood
Age: at birth (in 60%), <2 years (in 89%); M:F = 1.7:1
Path: well-marginated soft-tissue lesion 0.5 3 cm in diameter with scarlike consistency infiltration of surrounding tissues
Histo: spindle-shaped cells in short bundles and fascicles in periphery of lesion with features of both smooth muscle + fibroblasts; hemangiopericytoma-like pattern in center with necrosis, hyalinization, calcification

P.64


  • Solitary lesion (50 75%)

    Location: dermis, subcutis, muscle (86%); head, neck, trunk, bone (9%), GI tract (4%)
    Prognosis: spontaneous regression in 100%; recurrence after surgical excision in 7 10%

  • Multicentric disease (25 50%)

    Location: skin (98%), subcutis (98%), muscle (98%), bone (57%), viscera (25 37%): lung (28%), heart (16%), GI tract (14%), pancreas (9%), liver (8%)
    Prognosis: related to extent + location of visceral lesions with cardiopulmonary + GI involvement as harbingers of poor prognosis (death in 75 80%); spontaneous regression (33%)

  • firm nodules in skin, subcutis, muscle

  • overlying scarring of skin with ulceration

  • @ Skeleton

    Location: any bone may be involved; commonly in femur, tibia, rib, pelvis, vertebral bodies, calvarium; often symmetric
    Site: metaphysis of long bones

    • eccentric lobulated lytic foci with smooth margins 0.5 1.0 cm in size

    • well-defined with narrow zone of transition

    • initially no sclerosis; sclerotic margin with healing

    • osseous foci may increase in size and number

    • healing leaves little residual abnormality

    • unusual osseous findings:

      • periosteal reaction, pathologic fracture

      • vertebra plana, kyphoscoliosis with posterior scalloping of vertebral bodies

    • NUC (bone scan):

      • increased / little radiotracer uptake

      DDx: (1) Langerhans cell histiocytosis (skin lesions)
      (2) Neurofibromatosis (multiple masses)
      (3) Osseous hemangiomas / lymphangiomatosis / lipomatosis
      (4) Metastatic neuroblastoma
      (5) Multiple nonossifying fibromas
      (6) Enchondromatosis
      (7) Hematogenous osteomyelitis (unusual organism)
      (8) Fibrous dysplasia

  • @ Soft tissue

    • solid mass with central necrosis

    • central / peripheral solitary / multiple calcifications

    • prominent vascularity of skin lesions resembles hemangiomas

    • CT:

      • attenuation increased compared to muscle, before + after contrast enhancement

    • MR:

      • hypo- to hyperintense mass on T1WI + T2WI

      DDx: (1) Neurofibromatosis
      (2) Infantile fibrosarcoma, leiomyosarcoma
      (3) Angiomatosis

  • @ Lung

    • interstitial fibrosis, reticulonodular infiltrates

    • discrete mass

    • generalized bronchopneumonia

  • @ GI tract

    • diffuse narrowing / multiple small filling defects

Dermatomyositis

= autoimmune inflammatory myopathy with diffuse nonsuppurative inflammation of striated muscle + skin

Cause: cell-mediated (type IV) autoimmune attack on striated muscle
Pathophysiology: damaged chondroitin sulfate no longer inhibits calcification
Path: atrophy of muscle bundles followed by edema and coagulation necrosis, fibrosis, calcification
Histo: mucoid degeneration with round cell infiltrates concentrated around blood vessels
Age: bimodal: 5 15 and 50 60 years; M:F = 1:2

  • gradual onset of muscle weakness

  • elevated muscle enzymes (creatinine kinase, aldolase)

  • myositis-specific autoantibodies: anti-Jo-1

    • anti-aminoacyl-tRNA synthetase

      • arthritis, Raynaud phenomenon, fever, fatigue

      • interstitial lung disease

        Prognosis: requires prolonged treatment

    • anti-Mi-2 antibodies:

      • V-shaped chest rash (= shawl rash)

      • cuticular overgrowth

        Prognosis: good response to medication

    • anti-signal recognition particle antibodies

      • abrupt onset myositis heart involvement

  • @ Skeletal musculature

    Location: thigh (vastus lateralis + intermedius m. with relative sparing of rectus + biceps femoris m.) > pelvic girdle > upper extremity > neck flexors > pharyngeal muscles

    • bilateral symmetric edema in pelvic + thigh muscles

    • fatty infiltration + muscle atrophy (over months to years)

    • sheetlike confluent calcifications in soft tissues of extremities (quadriceps, deltoid, calf muscles), elbows, knees, hands, abdominal wall, chest wall, axilla, inguinal region) in 75%

  • @ Skeleton

    • pointing + resorption of terminal tufts

    • rheumatoid-like arthritis (rare)

    • floppy-thumb sign

      Cx: flexion contractures; soft-tissue ulceration

  • @ Chest

    • respiratory muscle weakness

    • disseminated pulmonary infiltrates (reminiscent of scleroderma)

    • diaphragmatic elevation with reduced lung volumes + basilar atelectasis

    • interstitial fibrosis (5 30%), most severely at lung bases:

      • fine reticular pattern progressing to coarse reticulonodular pattern + honeycombing

    • bronchiolitis obliterans organizing pneumonia

    • diffuse alveolar damage

    • HRCT:

      • predominantly linear abnormalities + ground-glass attenuation

      • air-space consolidation in middle + lower lung zones with peribronchial + subpleural distribution

        P.65


        Cx: aspiration pneumonia (most common finding due to pharyngeal muscle weakness)

  • @ Myocardium

    • changes similar to skeletal muscle

  • @ GI tract

    • progressive weakness of proximal striated muscle:

      • dysphagia

    • atony + dilatation of esophagus

    • atony of small intestines + colon

Clinical forms:

  • ACUTE FORM = childhood-onset form

    • fever, joint pain, lymphadenopathy, splenomegaly, subcutaneous edema

    • more severe dermatomyositis

      Prognosis: death within a few months

  • CHRONIC FORM = adult-onset form

    • = insidious onset with periods of spontaneous remission and relapse

    • low-grade fever, muscular aches + pains, edema

    • muscle weakness (due to active inflammation, necrosis, muscle atrophy with fatty replacement, steroid-induced myopathy)

    • first symptom in 50%

    • skin erythema: heliotrope rash (= dusky erythema of eyelids) with periorbital edema, Gottron sign (= scaly erythematous papules of knuckles, major joints and upper body)

    • first symptom in 25%

Cx: increased prevalence of malignant neoplasms of breast, prostate, lung, ovary, GI tract, kidney
Dx: muscle biopsy (normal in up to 15%)

Polymyositis

  • = involves skeletal muscle only

    Age: 4th decade

Desmoplastic Fibroma

  • = INTRAOSSEOUS DESMOID TUMOR

  • = rare locally aggressive benign neoplasm of bone with borderline malignancy resembling soft-tissue desmoids / musculoaponeurotic fibromatosis

Incidence: 107 cases in world literature
Histo: intracellular collagenous material in fibroblasts with small nuclei
Age: mean of 21 years (range 15 months to 75 years); in 90% <30 years; M:F = 1:1

  • slowly progressive pain + local tenderness

  • palpable mass

Location: mandible (26%), ilium (14%), >50% in long bones (femur [14%], humerus [11%], radius [9%], tibia [7%], clavicle), scapula, vertebra, calcaneus
Site: central meta- / diaphyseal (if growth plate open); may extend into epiphysis with subarticular location (if growth plate closed)

  • geographic (96%) / moth-eaten (4%) bone destruction without matrix mineralization

  • narrow (96%) / poorly defined (4%) zone of transition

  • no marginal sclerosis (94%)

  • residual columns of bone with pseudotrabeculae are CLASSIC (91%)

  • bone expansion (89%); may grow to massive size (simulating aneurysmal bone cyst / metastatic renal cell carcinoma)

  • breach of cortex + soft-tissue mass (29%)

Cx: pathologic fracture (9%)
Prognosis: 52% rate of local recurrence
Rx: wide excision
DDx: (1) Giant cell tumor (round rather than oval, may extend into epiphysis + subchondral bone plate)
(2) Fibrous dysplasia (occupies longer bone, contains mineralized matrix, often with sclerotic rim)
(3) Aneurysmal bone cyst (eccentric blowout appearance rather than fusiform)
(4) Chondromyxoid fibroma (eccentric with delicate marginal sclerosis + scalloped border)

Developmental Dysplasia of Hip (DDH)

  • = CONGENITAL DYSPLASIA OF HIP

  • = deformity of acetabulum due to disrupted relationship between femoral head and acetabulum

  • Acetabular dysplasia (without femoral subluxation / dislocation) can be determined only by imaging!

Etiology:

  • Late intrauterine event (98%)

    • mechanical:

      • oligohydramnios (restricted space in utero)

      • firstborn (tight maternal musculature)

        • in 60% of patients with DDH

      • breech position (hip hyperflexion results in shortening of iliopsoas muscle; L:R = 4:1)

        • in 30 50% of patients with DDH

        • only 2 4% of deliveries are breech

    • physiologic (females are more sensitive to):

      • maternal estrogen (not inactivated by immature fetal liver) blocks cross-linkage of collagen fibrils

      • pregnancy hormone relaxin

  • Teratologic (2%) due to a neuromuscular disorder (myelodysplasia, arthrogryposis) occurring during 12th 18th week GA

  • Postnatal onset (<1%)

Incidence: 0.15% of neonates (Australia 1%, Netherlands 3.7%, Poland 3.9%, Israel 5.9%, Austria 6.6%, Norway 16.9%)
Age: most dislocations probably occur after birth; M:F = 1:4 1:8; Caucasians > Blacks

Increased risk:

  • infants born in frank breech position (25%; risk of breech:vertex = 6 8:1)

  • congenital torticollis (10 20%)

  • skull-molding deformities; scoliosis; generalized joint laxity (Larsen syndrome, Ehlers-Danlos syndrome, Down syndrome [5%]); neuromuscular disorders (eg, myelodysplasia, spina bifida, sacral agenesis, arthrogryposis multiplex)

  • family history of DDH (6 20%): 6% risk for subsequent sibling of normal parents, 36% risk for subsequent sibling of one affected parent; 12% risk for patient's own children

  • foot deformities [metatarsus adductus, clubfoot (2%)

  • neonatal hyperextension of hips: swaddling of infants in hip extension / strapping to cradle board

P.66


Radiographic Lines of Hip Joint Position

Anatomy: acetabulum has a small bony component + a large cartilaginous component at birth; acetabulum highly susceptible for modeling within first 6 weeks of age + minimally susceptible >16 weeks of age

Classification:

  • Normal hip

  • Lax = subluxable hip

    • subluxability up to 6 mm is normal in newborns (still under influence of maternal hormones); decreasing to 3 mm by 2nd day of life

  • Concentric dislocatable unstable hip

    • = joint laxity allowing nondisplaced femoral head to become subluxed / dislocated under stress

      Incidence: 0.25 0.85% of all newborn infants (2/3 are firstborns)

    • Barlow positive

    • slight increase in femoral anteversion

    • mild marginal abnormalities in acetabular cartilage

    • early labral eversion

      Prognosis: 60% will become stable after 1 week; 88% will become stable by age of 2 months

  • Decentered subluxed hip

    • = femoral head shallow in location

    • loss of femoral head sphericity

    • increased femoral anteversion

    • early labral inversion

    • shallow acetabulum

  • Eccentric dislocated hip

    • = femoral head frankly displaced out of acetabulum

      • reducible = Ortolani positive

      • irreducible = Ortolani negative

    • accentuated flattening of femoral head

    • shallow acetabulum

    • limbus formation (= inward growth + hypertrophy of labrum)

  • hip click = usually result of joint capsule and tendon stretching + snapping (often confused with hip clunk )

    Acetabular Sector angles (in normal right hip)

  • positive examination result (up to 3 months of age):

    • positive Ortolani reduction test = reduction of proximal femur into the acetabulum by progressive abduction of flexed hips and knees associated with audible clunk

    • positive Barlow dislocation test = displacement of proximal femur by progressive adduction with downward pressure (piston maneuver) on flexed hips and knees associated with audible clunk

  • warning signs on physical examination:

    • limited hip abduction on affected side

    • shortening of thigh on affected side:

      • asymmetric thigh / buttock creases

      • Allis sign = Galeazzi sign = affected knee is lower with knees bent in supine position

      • Trendelenburg test = visible drooping + shortening on dislocated side with child standing on both feet, then one foot

Location: left:right:bilateral = 11:1:4

Radiologic lines:

  • Line of Hilgenreiner

    • = line connecting superolateral margins of triradiate cartilage

  • Acetabular angle / index

    • = slope of acetabular roof = angle that lies between Hilgenreiner's line and a line drawn from most superolateral ossified edge of acetabulum to superolateral margin of triradiate cartilage

  • Perkin's line

    • = vertical line to Hilgenreiner's line through the lateral rim of acetabulum

  • Shenton's curved line

    • = arc formed by inferior surface of superior pubic ramus (= top of obturator foramen) + medial surface of proximal femoral metaphysis to level of lesser trochanter

    • disruption of line (DDx: coxa valga)

  • Center-edge angle

    • = angle subtended by one line drawn from the acetabular edge to center of femoral head + second line perpendicular to line connecting centers of femoral heads

    • <25 suggests femoral head instability

AP pelvic radiograph: >6 8 weeks of age (von Rosen view = legs abducted 45 + thighs internally rotated)

  • Not reliable first 3 months of life!

  • proximal + lateral migration of femoral neck:

    P.67


    • eccentric position of proximal femoral epiphysis (position estimated by a circle drawn with a diameter equivalent to width of femoral neck)

    • interrupted discontinuous arc of Shenton's line

    • line drawn along axis of femoral shaft will not pass through upper edge of acetabulum but intersect the anterior-superior iliac spine (during Barlow maneuver)

    • apex of metaphysis lateral to edge of acetabulum

    • femoral shaft above horizontal line drawn through the Y-synchondroses

    • unilateral shortening of vertical distance from femoral ossific nucleus / femoral metaphysis to Hilgenreiner's line

    • femoral ossific nucleus / medial beak of femoral metaphysis outside inner lower quadrant of coordinates established by Hilgenreiner's + Perkin's lines

    acetabular dysplasia = shallow incompletely developed acetabulum:

  • acetabular angle >30 strongly suggests dysplasia

  • development of false acetabulum

  • delayed ossification of femoral epiphysis (usually evident between 2nd and 8th month of life)

US (practical only up to 4 6 months of age):

  • Too sensitive during first 2 weeks of life!

  • (1) static evaluation (popularized in Europe by Graf)

  • (2) dynamic evaluation (popularized in USA by Harcke)

  • @ Relationship of femoral head & acetabulum

    • femoral head position at rest in neutral position

    • hip instability under motion + stress maneuvers

    • dislocated (= eccentric) hip can be reduced (Ortolani positive):

      • hypoechoic femoral head not centered over triradiate cartilage between pubis + ischium (on transverse view)

      • increased amount of soft-tissue echoes ( pulvinar ) between femoral head and acetabulum

      • cartilaginous acetabular labrum interposed between head and acetabulum (inverted labrum)

      • posterior + superior dislocation of head against ilium

    • equator sign = <50% of femoral head lies medial to line drawn along iliac bone (on coronal view): >58% coverage is normal; 58% to 33% coverage is indeterminate; <33% coverage is abnormal

  • @ Femoral head

    • disparity in size of directly visualized unossified femoral head

    • disparity in presence + size of ossific nucleus

  • @ Acetabulum

    • delayed ossification of acetabular corner

    • wavy contour of bony acetabulum with only slight curvature

    • abnormally acute alpha angle (= angle between straight lateral edge of ilium + bony acetabular margin)

      • >60 in an infant is normal

      • 55 60 can be normal <4 weeks of age

      • <55 occurs in an immature acetabulum

      • 4 6 interobserver variation!

Prognosis: alpha-angle <50 at birth / 50 59 after 3 months indicates significant risk for dislocation without treatment; follow-up at 4-week intervals are recommended

No Caption Available.

P.68


CT:

  • sector angle = angle between line drawn from center of femoral head to acetabular rim + horizontal axis of pelvis (= reflection of acetabular support)

  • anterior acetabular sector angle <50

  • posterior acetabular sector angle <90

Cx: (1) Avascular necrosis of femoral head
(2) Intraarticular obstacle to reduction
   (a) pulvinar = fibrofatty tissue at apex of acetabulum
   (b) hypertrophy of ligamentum teres
   (c) labral hypertrophy / inversion
(3) Extraarticular obstacle to reduction (iliopsoas tendon impingement on anterior joint capsule with infolding of joint capsule)
Prognosis: 78% of hips become spontaneously normal by 4th week + 90% by 9th week
Rx: (1) Flexion-abduction-external rotation brace (Pavlik harness) / splint / spica cast
(2) Femoral varus osteotomy
(3) Pelvic (Salter) / acetabular rotation
(4) Increase in acetabular depth (Pemberton)
(5) Medialization of femoral head (Chiari)

Diastrophic Dysplasia

  • = DIASTROPHIC DWARFISM = EPIPHYSEAL DYSOSTOSIS

  • = autosomal recessive severe rhizomelic dwarfism secondary to generalized disorder of cartilage followed by fibrous scars + ossifications

  • diastrophic = twisted habitus

  • cauliflower ear = ear deformity from inflammation of pinna

  • laryngomalacia

  • lax + rigid joints with contractures

  • normal intellectual development

  • @ Axial skeleton

    • cleft palate (25%)

    • cervical spina bifida occulta

    • hypoplasia of odontoid

    • severe progressive kyphoscoliosis of lumbar spine (not present at birth)

    • narrowed interpedicular space in lumbar spine

    • short + broad bony pelvis

    • posterior tilt of sacrum

  • @ Extremities

    • severe micromelia (predominantly rhizomelic = humerus + femur shorter than distal long bones

    • widened metaphysis

    • flattened epiphysis (retardation of epiphyseal ossification) with invagination of ossification centers into distal ends of femora

    • multiple joint flexion contractures (notably of major joints)

    • dislocation of one / more large joints (hip, elbow), lateral dislocation of patella

    • coxa vara (common)

    • medially bowed metatarsals

    • clubfoot = severe talipes equinovarus

    • ulnar deviation of hands

    • oval + hypoplastic 1st metacarpal bone + abducted proximally positioned thumb = hitchhiker's thumb (CHARACTERISTIC)

    • bizarre carpal bones with supernumerary centers

    • widely spaced fingers

  • OB-US:

    • proportionately shortened long bones

    • hitchhiker thumb

    • clubfeet

    • joint contractures

    • abnormal spinal curvature

Prognosis: death in infancy (due to abnormal softening of tracheal cartilage)

Diffuse Idiopathic Skeletal Hyperostosis

  • = DISH = FORESTIER DISEASE = ANKYLOSING HYPEROSTOSIS

  • = common ossifying diathesis characterized by bone proliferation at sites of tendinous + ligamentous attachment (enthesis)

Etiology:

  • may be caused by altered vitamin A metabolism (elevated plasma levels of unbound retinol)

  • long-term ingestion of retinoid derivatives for treatment of acne (eg, Accutane );

? hypertrophic variant of spondylosis deformans

Age: >50 years; M:F = 3:1

  • pain, tenderness in extraspinal locations

  • restricted motion of vertebral column

  • hyperglycemia

  • positive HLA-B27 in 34%

  • increased incidence of hyperostosis frontalis interna

  • @ Spine

    Location: middle + lower thoracic > lower cervical > entire lumbar spine

    • flowing ossification of at least 4 contiguous vertebral bodies:

      • osteophytes located anteriorly + laterally on right side (not on left because of aorta)

      • osteophytes largest at level of intervertebral disk

      • radiolucency beneath deposited bone

    • disk spaces well preserved, no apophyseal ankylosis, no sacroiliitis

  • @ Pelvis

    • bridge across superior aspect of symphysis pubis

    • ossification of iliolumbar + sacrotuberous + sacroiliac ligaments (high probability for presence of spinal DISH, DDx: fluorosis)

    • whiskering at iliac crest, ischial tuberosity, trochanters

    • broad osteophytes at lateral acetabular edge, inferior portions of sacroiliac joints

  • @ Extremities

    • big heel spurs (on plantar + posterior surface of calcaneus)

    • spur of olecranon process of ulna

    • spur on anterior surface of patella

    • ossification of coracoclavicular ligament, patellar ligament, tibial tuberosity, interosseous membranes

Cx: postoperative heterotopic bone formation (hip)
DDx: (1) Fluorosis (increased skeletal density)
(2) Acromegaly (posterior scalloping, skull features)
(3) Hypoparathyroidism
(4) X-linked hypophosphatemic vitamin D resistant rickets

P.69


(5) Ankylosing spondylitis (squaring of vertebral bodies, coarser syndesmophytes, sacroiliitis, apophyseal alteration)
(6) Intervertebral osteochondrosis (vacuum phenomenon, vertebral body marginal sclerosis, decreased intervertebral disk height)

Dislocation

Hip Dislocation

Incidence: 5% of all dislocations

  • POSTERIOR HIP DISLOCATION (80 85%)

    Mechanism: classical dashboard injury (= flexed knee strikes dashboard)
    Associated with: fractures of posterior rim of acetabulum, femoral head

    • adducted lower extremity flexed at hip

  • ANTERIOR HIP DISLOCATION (5 10%)

    Mechanism: forced abduction + external rotation
    Associated with: fractures of acetabular rim, greater trochanter, femoral neck, femoral head (characteristic depression on posterosuperior and lateral portion)

    • anterior obturator dislocation

    • superoanterior / pubic hip dislocation

    • lower extremity in external rotation

    • prominent lesser trochanter

    • obturator position of femoral head

  • CENTRAL ACETABULAR FRACTURE-DISLOCATION

    Mechanism: force applied to lateral side of trochanter

Patellar Dislocation

= TRANSIENT LATERAL PATELLAR DISLOCATION

Incidence: 2 3% of all knee injuries
Mechanism: during attempt to slow forward motion while pivoting medially on a planted foot; internal rotation of femur on fixed tibia while knee is flexed + quadriceps contraction produces a net lateral force
At risk: shallow trochlear groove
Associated with: medial meniscal tear / major ligamentous injury in 31%
Age: young physically active people

  • hemarthrosis (most common cause of hemarthrosis in young conscripts)

  • swelling + tenderness of medial retinaculum

  • >50% not clinically diagnosed initially!

  • increased signal intensity / thickening / disruption of medial patellar retinaculum

  • lateral patellar tilt

  • contusion / microfracture / osteochondral injury of nonarticular surface of lateral femoral condyle + medial articular surface of patella

  • hemarthrosis

MR:

  • bone contusion of anterolateral aspect of lateral femoral condyle + inferomedial aspect of patella

  • sprain / disruption / avulsion of medial retinaculum + medial patellofemoral ligament + medial patellotibial lig.

    Mr Imaging Signs of Patellar Dislocation

  • elevation of vastus medialis obliquus muscle

Rx: (1)Temporary immobilization + rehabilitation: successful in 75%
(2) Surgery: fixation of osteochondral fragments, medial capsule repair, lateral retinacular release, vastus medialis et lateralis rearrangement, medial retinaculum reefing

Shoulder Dislocation

Sternoclavicular Dislocation (3%)

 

Acromioclavicular Dislocation (12%)

Grade 1 = soft-tissue swelling + no joint widening
Grade 2 = subluxation with elevation of clavicle of <5 mm (weight-bearing!)
Grade 3 = dislocation with wide AC joint + increased coracoclavicular distance

Glenohumeral Dislocation (85%)

  • Glenohumeral joint dislocations make up >50% of all dislocations!

Anterior / Subcoracoid Shoulder Dislocation

(95% of all shoulder dislocations)

Types: subcoracoid, subglenoid, subclavicular, intrathoracic
Mechanism: external rotation + abduction (fall on outstretched arm / hand behind occiput); 40% recurrent
Age: in younger individuals in their teens

  • Bankart lesion = anterior capsulolabral avulsion

    • = avulsion of anterior-inferior glenoid labrum including labral insertion of inferior glenoid ligament

      [Arthur Sydney Blundell Bankart (1879 1951), British orthopedic surgeon]

May be associated with:

  • bony Bankart fracture of anterior rim of glenoid

  • fracture of greater tuberosity (15%)

  • Hill-Sachs defect (50%) = depression / impacted fracture of posterolateral surface of humeral head at / above level of coracoid process (due to impaction against anterior edge of glenoid rim in subglenoid type)

    [Harold Arthur Hill (1901 1973) and Maurice David Sachs (1909 1987), radiologists in San Francisco, CA]

P.70


MRI (arthrography improves sensitivity to 89 99%, and specificity to >90%):

  • hemorrhagic effusion (in acute injury)

  • increased signal intensity in anterior-inferior labrum + capsule (DDx: magic angle artifact)

  • labrum + capsule lifted away from glenoid

  • discrete tear / fragmentation of labrum

  • tear of middle glenohumeral ligament

  • fracture of anterior-inferior glenoid

  • tear of degenerated supraspinatus tendon (in 33% of patients >40 years of age)

  • tear of degenerated subscapularis tendon (in 33% of patients >40 years of age)

  • greater-tuberosity humeral fracture (in 33%)

  • paralabral cysts are usually associated with labral tears; may cause denervation of suprascapular nerve simulating impingement syndrome (DDx: age-related degeneration)

Cx: (1) Recurrent dislocations (in up to 90% of young active individuals)
(2) Repeated dislocations due to incomplete / inadequate healing = chronic recurrent anterior shoulder instability
(3) Arthritis (with repeated subluxations)
Rx: (1) Conservative treatment for most
(2) Surgical fixation for young athletes

Posterior Shoulder Dislocation (2 4%)

Cause: (a)traumatic: convulsive disorders /electric shock therapy
(b) nontraumatic: voluntary, involuntary, congenital, developmental
Types: subacromial, subglenoid, subspinous

  • In >50% unrecognized initially + subsequently misdiagnosed as frozen shoulder!

  • Average interval between injury and diagnosis is 1 year!

  • rim sign (66%) = distance between medial border of humeral head + anterior glenoid rim <6 mm

May be associated with:

  • trough sign (75%) = reverse Hill-Sachs = compression fracture of anteromedial humeral head (tangential Grashey view of glenoid!)

  • fracture of posterior glenoid rim

  • avulsion fracture of lesser tuberosity

MRI:

  • tear of subscapularis tendon

  • empty bicipital groove (= dislocated bicipital tendon)

Inferior Shoulder Dislocation (1 2%)

  • = LUXATIO ERECTA

  • = extremity held over head in fixed position with elbow flexed

Mechanism: severe hyperabduction of arm resulting in impingement of humeral head against acromion

  • humeral articular surface faces inferiorly

Cx: rotator cuff tear; fracture of acromion inferior glenoid fossa greater tuberosity; neurovascular injury

No Caption Available.

Superior Shoulder Dislocation (<1%)

= humeral head driven upward through rotator cuff

May be associated with: fracture of humerus, clavicle, acromion
DDx: drooping shoulder (transient phenomenon after fracture of surgical neck of humerus due to hemarthrosis / muscle imbalance)

Gadolinium Shoulder Arthrography

  • fluoroscopically guided needle insertion from an anterior approach

  • confirmation of needle placement with iodinated contrast material

  • injection of 12 20 mL of diluted gadolinium chelate solution:

    • 0.1 mL of gadolinium DTPA (469 mg/mL) into

    • 20 mL of bacteriostatic saline

  • patient's arm and shoulder are moved through full range of motion

Wrist Dislocation

Mechanism: fall on outstretched hand
Incidence: 10% of all carpal injuries

Lunate Dislocation

 

Perilunate Dislocation

  • 2 3 times more common than lunate dislocation

    accompanied by fracture in 75% (= transscaphoid perilunate dislocation)

  • most commonly dorsal dislocation

Rotary Subluxation of Scaphoid

= tearing of interosseous ligaments of lunate, scaphoid, capitate

Mechanism: acute dorsiflexion of wrist; may be associated with rheumatoid arthritis

  • gap >4 mm between scaphoid + lunate (PA view)

  • foreshortening of scaphoid

  • ring sign of distal pole of scaphoid

Midcarpal Dislocation

 

Down Syndrome

= MONGOLISM = TRISOMY 21

Chromosomes: 95% nondisjunction, 5% translocation
Incidence: 1:870 live births, most common karyotype / chromosomal abnormality in USA

P.71


  • mental retardation

  • hypotonia in infancy

  • characteristic facies

  • Simian crease

  • @ Skull

    • hypotelorism

    • persistent metopic suture (40 79%) after age 10

    • hypoplasia of sinuses + facial bones

    • microcrania (brachycephaly)

    • delayed closure of sutures + fontanels

    • dental abnormalities (underdeveloped tooth No. 2)

    • flat-bridged nose

  • @ Axial skeleton

    • atlantoaxial subluxation (25%)

    • anterior scalloping of vertebral bodies

    • squared vertebral bodies = centra high and narrow = positive lateral lumbar index (ratio of horizontal to vertical diameters of L2)

  • @ Chest

    • congenital heart disease (40%): endocardial cushion defect, VSD, tetralogy of Fallot

    • hypersegmentation of manubrium = 2 3 ossification centers (90%)

    • gracile ribs; 11 pairs of ribs (25%)

  • @ Pelvis (frontal view)

    • flaring of iliac wings (= rotation of iliac wings toward coronal plane at sacroiliac joints) = Mickey Mouse ears / elephant ears :

      • decreased iliac angle + index (in 70 80%)

    • flattening of acetabular roof (small acetabular angle)

    • elongated + tapered ischia

  • @ Extremities

    • metaphyseal flaring

    • clinodactyly (50%); widened space between first two digits of hands + feet

    • hypoplastic and triangular middle + distal phalanges of 5th finger = acromicria (DDx: normal individuals, cretins, achondroplastic dwarfs)

    • pseudoepiphyses of 1st + 2nd metacarpals

  • @ Gastrointestinal

    • umbilical hernia

    • double bubble sign (8 10%) = duodenal atresia / stenosis / annular pancreas

    • tracheoesophageal fistula

    • anorectal anomalies

    • Hirschsprung disease

    OB-US:

    • advanced maternal age

      • In 1:385 live births for women >35 years of age

      • HOWEVER: 80% of fetuses with Down syndrome are born to mothers <35 years of age

    • quad test (2nd trimester maternal serum screening):

      • low (0.7 MoM) maternal alpha-fetoprotein (20 30%)

      • increased (2.04 MoM) hCG (DDx: decreased in trisomy 18)

      • decreased (0.79 MoM) unconjugated estriol (uE3)

      • decreased dimeric inhibin A levels

      • optimal time for test between 15 and 16 weeks GA

      • detects 75% of cases with Down syndrome with a 5% screen-positive rate

      Disadvantage: late performance in 2nd trimester, 25% of Down syndrome cases not detected, many amniocenteses unnecessarily recommended

    • low pregnancy-associated plasma protein A (PAPP-A @ 10 14 weeks EGA

    • first-trimester ultrasound markers:

      • nuchal translucency

        • = measurement of space between spine and overlying skin on midsagittal view

          Best time: 10w3d 13w6d EGA

        • 5 mm during 14 18 weeks

        • 6 mm during 19 24 weeks

          Cause: heart failure, abnormal extracellular matrix, abnormal lymphatic development

      • absent nasal bone

        Best time: between 10 and 14 weeks EGA

      • absent / reversed Doppler flow in ductus venosus during atrial contraction

    • major structural malformations:

      Best time: 18 weeks EGA

      • VSD / complete AV canal (50%)

      • cystic hygroma, resolved by 20th week MA (DDx: Turner syndrome, trisomy 18, trisomy 13, triploidy)

      • omphalocele

      • double bubble of duodenal atresia (8 10%), not apparent before 22 weeks GA

      • hydrothorax

      • mild cerebral ventricular dilatation

      • agenesis of corpus callosum

      • imperforate anus

      minor markers:

      • elevated BPD / femur ratio (secondary to short femur)

      • ratio of measured-to-expected femur length 0.91 [expected femur length: 9.3105 + 0.9028 BPD] (sensitivity 40%, specificity 95%, false-positive rate of 2 7%, 0.3% PPV for low-risk population [1:700], 1% PPV for high-risk population [1:250])

      • ratio of measured-to-expected humerus length 0.90 [expected humerus length: 7.9404 + 0.8492 BPD] (1 2% PPV for low-risk population; 3% PPV for high-risk population)

      • flared iliac crest = iliac wings rotated toward coronal plane:

        • mean iliac angle at superiormost level of 95.6 11.7 (compared to 76.4 16.8 for euploid fetuses)

      • sandal-gap deformity = separation of great toe (45%)

      • hypoplasia of middle phalanx of 5th digit resulting in clinodactyly (= inward curve) in 60%

      • mild fetal pyelectasis (17 25%)

      • echogenic bowel at <20 weeks GA (15%, in 0.6% of normals)

      • echogenic intracardiac focus, usually in left ventricle = thickening of papillary muscle (18%, in 5% of normals)

      • frontal lobe shortening (measured from the inner table of the frontal bone to the posterior margin of the thalamus)

      • brachycephaly

      • small cerebellum

      • IUGR (in 30%)

      • polyhydramnios

    Cx: leukemia (increased frequency 3 20 x)

P.72


Dyschondrosteosis

  • = L RI-LAYANI-WEILL SYNDROME

  • = mesomelic long-bone shortening (forearm + leg); autosomal dominant

  • M:F = 1:4

  • limited motion of elbow + wrist

  • bilateral Madelung deformity:

    • radial shortening in relation to ulna

    • bowing of radius laterally + dorsally

    • dorsal subluxation of distal end of ulna

    • carpal wedging between radius + ulna (due to triangular shape of distal radial epiphysis + underdevelopment of ulna)

DDx: pseudo-Madelung deformity (from trauma / infection)

Dysplasia Epiphysealis Hemimelica

  • = TREVOR DISEASE = TARSOEPIPHYSEAL ACLASIS

  • = uncommon skeletal developmental disorder representing an epiphyseal osteochondroma

Incidence: 1:1,000,000
Age: 2 4 years; M:F = 3:1
Cause: failure of normal progression of cellular cartilage breakdown (= aclasis); spontaneous occurrence
Path: lobulated mass protruding from epiphysis with a cartilaginous cap
Histo: normal bone + hyaline cartilage with abundant enchondral ossification (= abnormal cellular activity at cartilaginous ossification center)

Types:

  • Localized form = monostotic involvement: usually hindfoot and ankle

  • Classic form (>66%) = more than one area of involvement in a single extremity with characteristic hemimelic distribution: talus, distal femur, distal tibia

  • Generalized / severe form = disease involving the whole lower extremity

    • pelvic involvement: femoral head, symphysis pubis, triradiate cartilage

    • hypertrophy of ipsilateral iliac bone

  • antalgic (= pain-avoiding) gait; palpable mass

  • varus / valgus deformity; limb length discrepancy

  • limited joint mobility and function

Location: lower extremity (tarsus, knee, ankle); rare in upper extremity (humerus, ulna, scapula)
Site: restricted to medial OR lateral side of limb (= hemimelic), ie, medial:lateral = 2:1

  • @ Infant & toddler

    • premature appearance of an eccentric, lobulated, overgrown, asymmetric ossification center

    • stippled calcification of anomalous cartilage

  • @ Childhood

    • disorganized epiphyseal calcification accompanied by irregular ossification

    • osteochondroma-like growth from one side of epiphysis

    • premature closure of physis results in limb deformity and limb length discrepancy

    • irregular articular surface combined with angular deformity

    • undertubulation of bone as a consequence of secondary involvement of metaphysis

Cx: premature secondary osteoarthritis
DDx: osteochondroma

Echinococcus of Bone

Occurs occasionally in the USA; usually in foreign-born individuals; bone involvement in 1%

Histo: no connective tissue barrier; daughter cysts extend directly into bone

  • Pelvis, sacrum, rarely long tubular bones

    • round / irregular regions of rarefaction

    • multiloculated lesion (bunch of grapes)

    • no sharp demarcation (DDx: chondroma, giant cell tumor) with secondary infection:

      • thickening of trabeculae with generalized perifocal condensation

      • cortical breakthrough with soft-tissue mass

  • Vertebra

    • sclerosis without pathologic fracture

    • intervertebral disks not affected

    • vertebral lamina often involved

    • frequently involvement of adjacent ribs

Ehlers-Danlos Syndrome

= group of autosomal dominant diseases of connective tissue characterized by abnormal collagen synthesis

Types: 10 types have been described that differ clinically, biochemically, and genetically
Age: present at birth; predominantly in males

  • hyperelasticity of skin

  • fragile brittle skin with gaping wounds and poor healing

  • molluscoid pseudotumors over pressure points

  • hyperextensibility of joints

  • joint contractures with advanced age

  • bleeding tendency (fragility of blood vessels)

  • blue sclera, microcornea, myopia, keratoconus, ectopia lentis

  • @ Soft tissues

    • multiple ovoid calcifications (2 10 mm) in subcutis / in fatty cysts ( spheroids ), most frequently in periarticular areas of legs

    • ectopic bone formation

  • @ Skeleton

    • hemarthrosis (particularly in knee)

    • malalignment / subluxation / dislocation of joints on stress radiographs

    • recurrent dislocations (hip, patella, shoulder, radius, clavicle)

    • precocious osteoarthrosis (predominantly in knees)

    • ulnar synostosis

    • kyphoscoliosis

    • spondylolisthesis

    • spina bifida occulta

  • @ Chest

    • diaphragmatic hernia

    • panacinar emphysema + bulla formation

    • tracheobronchomegaly + bronchiectasis

  • @ Arteries

    • aneurysm of great vessels, aortic dissection, tortuosity of arch, ectasia of pulmonary arteries

    • AORTOGRAPHY CONTRAINDICATED!

      (Cx following arteriography: aortic rupture, hematomas)

  • GI tract

    • ectasia of gastrointestinal tract

P.73


Elastofibroma

= benign tumorlike lesion forming as a reaction to mechanical friction

Incidence: in 24% of women + 11% of men >55 years (autopsy study)
Age: elderly; M:F = 1:2
Histo: enlarged irregular serrated elastic hypereosinophilic fibers, collagen, scattered fibroblasts, occasional lobules of adipose tissue

  • asymptomatic

  • may remain clinically inapparent

    Location: between inferior margin of scapula + posterior chest wall; bilateral in 25%

  • inhomogeneous poorly defined lesion of soft-tissue attenuation similar to muscle

  • well-defined intermediate-signal intensity lesion with interlaced areas of fat-intensity signal on T1WI + T2WI

Enchondroma

= benign cartilaginous growth in medullary cavity; bones preformed in cartilage are affected (NOT skull)

Incidence: 3 17% of biopsied primary bone tumors
Second most common cartilage-containing tumor!
Etiology: continued growth of residual benign rests of cartilage displaced from the growth plate
Age: 10 30 years; M:F = 1:1
Histo: lobules of pure hyaline cartilage

usually asymptomatic, painless swelling

Location: (usually solitary; multiple = enchondromatosis)
(a) in 40% small tubular bones of wrists + hand (most frequent tumor here), distal + mid aspects of metacarpals, proximal / middle phalanges
(b) proximal femur, proximal humerus, tibia, radius, ulna, foot, rib (3%)
Site: central within medullary canal + metaphyseal; epiphysis only affected after closure of growth plate

  • oval / round area of geographic destruction with lobulated contour + fine marginal line

  • cortical endosteal scalloping

  • ground-glass appearance

  • dystrophic calcifications within small cartilage nodules / fragments of lamellar bone: pinhead, stippled, flocculent, rings and arcs pattern

  • bulbous expansion of bone with thinning of cortex in small tubular bones of phalanx, rib, fibula

  • Madelung deformity = bowing deformities of limb, discrepant length

  • NO cortical breakthrough / periosteal reaction

  • MR:

    • low- to intermediate-signal intensity on T1WI + high-signal intensity on T2WI

    • low-signal intensity matrix calcifications

    • normal fat marrow interspersed between cartilage nodules

    • peripheral enhancement pattern

Cx: (1) Pathologic fracture
(2) Malignant degeneration in long-bone enchondromas in 15 20% (gradually increasing pain in an adult patient)
DDx: (1) Epidermoid inclusion cyst (phalangeal tuft, history of trauma, more lucent)
(2) Unicameral bone cyst (rare in hands, more radiolucent)
(3) Giant cell tumor of tendon sheath (commonly erodes bone, soft-tissue mass outside bone)
(4) Fibrous dysplasia (rare in hand, mostly polyostotic)
(5) Bone infarct
(6) Chondrosarcoma (exceedingly rare in phalanges, metacarpals, metatarsals)

Enchondromatosis

  • = OLLIER DISEASE = DYSCHONDROPLASIA = MULTIPLE ENCHONDROMATOSIS

  • = nonhereditary failure of cartilage ossification

Cause: derangement of cartilaginous growth resulting in migration of cartilaginous rests from epiphyseal plate into metaphysis where they proliferate
Age: early childhood presentation
Association: juvenile granulosa cell tumor of ovary

  • growth disparity with leg / arm shortening

  • hand + feet deformity

Location: predominantly unilateral monomelic distribution (a) localized (b) regional (c) generalized

  • well-demarcated rounded radiolucencies / columnar streaks of decreased density from epiphyseal plate into diaphysis of long bones = cartilaginous rests

  • expansile remodeling of affected bone:

    • clublike deformity / expansion of metaphyseal region

    • predominant thinning of cortex + endosteal scalloping

    • bony spurs pointing toward the joint (DDx: exostosis points away from it)

  • cartilaginous areas show punctate calcifications with age:

    • matrix mineralization with TYPICAL arc-and-ring appearance of chondroid lesions

  • associated with dwarfing of the involved bone due to impairment of epiphyseal fusion

  • bowing deformities of limb bones

  • discrepancy in length = Madelung deformity (radius, ulna)

  • small bones of feet + hands: aggressive deforming tumors that may break through cortex secondary to tendency to continue to proliferate

  • fanlike radiation of cartilage from center to crest of ilium

Cx: sarcomatous transformation (in 25 30%): osteosarcoma (young adults); chondro- / fibrosarcoma (in older patients)

Maffucci Syndrome

  • = nonhereditary mesodermal dysplasia characterized by enchondromatosis + multiple soft-tissue cavernous hemangiomas + less commonly lymphangiomas

    Age: 25% during 1st year of life; 45% prior to 6 years; 78% before puberty; M > F
    Association: juvenile granulosa cell tumor of ovary

    • multiple blue subcutaneous nodules particularly on digits + extremities (cavernous hemangiomas)

    • normal intelligence

    Location: unilateral involvement (50%) / marked asymmetry; distinct predilection for tubular bones of hands + feet

    P.74


    • phleboliths may be present

    • striking tendency for enchondromas to be very large projecting into soft tissues

    • growth disturbance of long bones (common)

    Cx: (a) malignant transformation of
       (1) Enchondroma to chondrosarcoma / fibrosarcoma (15 20%)
       (2) Cavernous hemangioma to hemangiosarcoma / hemangioendothelioma / lymphangiosarcoma (in 3 5%)
    (b) increased prevalence of ovarian carcinoma, pancreatic carcinoma, CNS glioma, gastrointestinal adenocarcinoma
    Prevalence of malignancy: 23 100%
    DDx: Ollier disease (without hemangiomas)

Engelmann-Camurati Disease

= PROGRESSIVE DIAPHYSEAL DYSPLASIA = CAMURATI-ENGELMANN DISEASE

Cause: autosomal dominant; disturbance in intramembranous bone formation + modeling (as occurs in cortex of long bones, calvaria, mandible, facial bones, midsegment of clavicle)
Age: 5 25 years (primarily in childhood); M > F

  • neuromuscular dystrophy = delayed walking (18 24 months) with wide-based waddling gait; often misdiagnosed as muscular dystrophy / poliomyelitis

  • weakness + easy fatigability in legs

  • bone pain + tenderness usually in midshaft of long bones

  • underdevelopment of muscles secondary to malnutrition

  • NORMAL laboratory values

Location: usually symmetrical; NO involvement of hands, feet, ribs, scapulae

  • @ Skull (initially affected)

    • amorphous increase in density at base of skull

    • encroachment of frontal + sphenoid sinus; sparing of maxillary sinus

  • @ Long bones (bilateral symmetrical distribution)

    Site: tibia > femur > fibula > humerus > ulna > radius

    • fusiform enlargement of diaphyses with cortical thickening (endosteal + periosteal accretion of mottled new bone) and progressive obliteration of medullary cavity

    • progression of lesions along long axis of bone toward either end

    • abrupt demarcation of lesions (metaphyses + epiphyses spared)

    • relative elongation of extremities

DDx: (1) Chronic osteomyelitis (single bone)
(2) Hyperphosphatasemia (high alkaline phosphatase levels)
(3) Paget disease (age, new-bone formation, increased alkaline phosphatase)
(4) Infantile cortical hyperostosis (fever; mandible, rib, clavicles; regresses, <1 year of age)
(5) Fibrous dysplasia (predominantly unilateral, subperiosteal new bone)
(6) Osteopetrosis (very little bony enlargement)
(7) Vitamin A poisoning

Epidermoid Cyst

  • = INFUNDIBULAR CYST

  • = proliferation of surface epidermal cells within the dermis

    Histo: production of keratin within closed space lined by surface epidermis
    Associated with: nevoid basal cell syndrome (Gorlin syndrome) patients have a high prevalence of epidermoid / dermoid cysts

  • isointense / slightly hyperintense relative to muscle on T1WI

  • hyperintense with focal areas of decreased signal on T2WI

Epidermoid Inclusion Cyst

= INTRAOSSEOUS KERATIN CYST = IMPLANTATION CYST

Age: 2nd 4th decade; M > F
Histo: stratified squamous epithelium, keratin, cholesterol crystals (soft white cheesy contents)

  • history of trauma (implantation of epithelium under skin with secondary bone erosion)

  • asymptomatic

Location: superficially situated bones such as calvarium (typically in frontal / parietal bone), phalanx (usually terminal tuft of middle finger), L > R hand, occasionally in foot

  • well-defined round osteolysis with sclerotic margin

  • cortex frequently expanded + thinned

  • NO calcifications / periosteal reaction / soft-tissue swelling

  • pathologic fracture often without periosteal reaction

DDx: (a) in finger: glomus tumor, enchondroma (rare in terminal phalanx)
(b) in skull: infection, metastasis (poorly defined), eosinophilic granuloma (beveled margin)

Epiphyseolysis of Femoral Head

  • = SLIPPED CAPITAL FEMORAL EPIPHYSIS

  • = atraumatic fracture through hypertrophic zone of physeal plate

Frequency: 2:100,000 people
Etiology: growth spurt, renal osteodystrophy, rickets, childhood irradiation, growth hormone therapy, trauma (Salter-Harris type I epiphyseal injury)
Pathogenesis: widening of physeal plate during growth spurt + change in orientation of physis from horizontal to oblique increases shear forces
Age: overweight 8 17 year old boys (mean age for boys 13, for girls 11 years); M:F = 3:1; black > white

Associated with:

  • malnutrition, endocrine abnormality, developmental dysplasia of hip (during adolescence)

  • delayed skeletal maturation (after adolescence)

  • hip pain (50%) / knee pain (25%) for 2 3 weeks

Location: usually unilateral; bilateral in 20 37% (at initial presentation in 9 18%)

  • widening of epiphyseal growth plate (preslip phase):

    • irregularity + blurring of physeal physis

    • demineralization of neck metaphysis

  • posteromedial displacement of head (acute slip):

    • decrease in neck-shaft angle with alignment change in the growth plate to a more vertical orientation

    • line of Klein (= line drawn along superior edge of femoral neck) fails to intersect the femoral head

      Line of Klein in Normal Hip

      • P.75


    • epiphysis appears smaller due to posterior slippage:

      early slips are best seen on cross-table LAT view

      CAVE: positioning into a frog leg view may cause further displacement

  • sclerosis + irregularity of widened physis (chronic slip):

    • metaphyseal blanch sign = area of increased opacity in proximal part of metaphysis (healing response)

Grading (based on femoral head position):

mild = displaced by <1/3 of metaphyseal diameter
moderate = displaced by 1/3 2/3 of diameter
severe = displaced by >2/3 of metaphyseal diameter
Cx: (1) Chondrolysis = acute cartilage necrosis (7 10%) = rapid loss of >50% of thickness of cartilage
    joint space <3 mm
(2) Avascular necrosis of femoral head (10 15%): risk increases with advanced degree of slip, delayed surgery for acute slip, anterior pin placement, large number of fixation pins, subcapital osteotomy
(3) Pistol-grip deformity = broadening + shortening of femoral neck in varus deformity
(4) Degenerative osteoarthritis (90%)
(5) Limb-length discrepancy due to premature physeal closure
Rx: (1) limitation of activity
(2) prophylactic pinning
(3) osteotomy
Attempted reductions increase risk of AVN!

Essential Osteolysis

= progressive slow bone-resorptive disease

Histo: proliferation + hyperplasia of smooth muscle cells of synovial arterioles

  • progressive osteolysis of carpal + tarsal bones

  • thinned pointed proximal ends of metacarpals + metatarsals

  • elbows show same type of destruction

  • bathyrocephalic depression of base of skull

DDx: (1) Massive osteolysis = Gorham disease (local destruction of contiguous bones, usually not affecting hands / feet)
(2) Mutilating forms of rheumatoid arthritis
(3) Tabes dorsalis
(4) Leprosy
(5) Syringomyelia
(6) Scleroderma
(7) Raynaud disease
(8) Regional posttraumatic osteolysis
(9) Ulcero-mutilating acropathy
(10) Mutilating forms of rheumatoid arthritis
(11) Acrodynia mutilante (nonhereditary)

Ewing Sarcoma

= EWING TUMOR

Incidence: 4 10% of all bone tumors (less common than osteo- / chondrosarcoma); most common malignant bone tumor in children; 4th most common bone tumor overall

  • Clinically, radiologically, and histologically very similar to PNET!

Histo: small round cells, uniformly sized + solidly packed (DDx: lymphoma, osteosarcoma, myeloma, neuroblastoma, carcinoma, eosinophilic granuloma) invading medullary cavity and entering subperiosteum via Haversian canals producing periostitis, soft-tissue mass, osteolysis; glycogen granules present (DDx to reticulum cell sarcoma); absence of alkaline phosphatase (DDx to osteosarcoma); MIC2 cell surface immunoreactivity (in 100%)
Age: peak 15 years (range 5 months to 54 years); in 95% 4 25 years; in 30% <10 years; in 39% 11 15 years; in 31% >15 years; in 50% <20 years;M:F = 1:2; Caucasians in 96%

  • severe localized pain

  • soft-tissue mass

  • fever, leukocytosis, anemia (in early metastases) simulating infection

Location:

  • femur (25%), pelvis-ilium (14%), tibia (11%), humerus (10%), fibula (8%), ribs (6 10%)

  • long bones in 60%: metadiaphysis (44%), middiaphysis (33%), metaphysis (15%), metaepiphyseal (6%), epiphyseal (2%); usually no involvement of epiphysis as tumor originates in medullary cavity with invasion of Haversian system

  • flat bones in 40%: pelvis, scapula, skull, vertebrae (in 3 10%; sacrum > lumbar > thoracic > cervical spine); ribs (in 7% > age 10; in 30% < age 10)

    • >20 years of age predominantly in flat bones

    • <20 years of age predominantly in cylindrical bones (tumor derived from red marrow)

  • 8 10 cm long lytic lesion in shaft of long bone (62% lytic, 23% mixed density, 15% dense)

  • mottled moth-eaten destructive permeative lesion (72%) (late finding)

  • penetration into soft tissue (55%) with preservation of tissue planes (DDx: osteomyelitis with diffuse soft-tissue swelling)

  • early fusiform lamellated onionskin periosteal reaction (53%) / spiculated = sunburst / hair-on-end (23%), Codman triangle

  • cortical thickening (16%)

  • cortical destruction (18%)

  • cortical sequestration

  • reactive sclerotic new bone (30%)

  • bone expansion (12%)

  • @ Ewing sarcoma of rib:

    • primarily lytic / sclerotic / mixture of lysis + sclerosis

    • disproportionately large inhomogeneous soft-tissue mass

    • large intrathoracic + minimal extrathoracic component

      • P.76


    • may spread into spinal canal via intervertebral foramen

Metastases to: lung, bones, regional lymph nodes in 11 30% at time of diagnosis, in 40 45% within 2 years of diagnosis
Cx: pathologic fracture (5 14%)
Prognosis: 60 75% 5-year survival
DDx: (1) Multiple myeloma (older age group)
(2) Osteomyelitis (duration of pain <2 weeks)
(3) Eosinophilic granuloma (solid periosteal reaction)
(4) Osteosarcoma (ossification in soft tissue, near age 20, no lamellar periosteal reaction)
(5) Reticulum cell sarcoma (clinically healthy, between 30 and 50 years, no glycogen)
(6) Neuroblastoma (< age 5)
(7) Anaplastic metastatic carcinoma (>30 years of age)
(8) Osteosarcoma
(9) Hodgkin disease

Extramedullary Hematopoiesis

  • = compensatory response to deficient bone marrow blood cell production

    Etiology: prolonged erythrocyte deficiency due to

    • destruction of RBC:

      • congenital hemolytic anemia (sickle cell anemia, thalassemia, hereditary spherocytosis), acquired hemolytic anemia, idiopathic severe anemia, erythroblastosis fetalis

    • inability of normal blood-forming organs to produce erythrocytes: iron deficiency anemia, pernicious anemia, myelofibrosis, myelosclerosis, polycythemia vera, carcinomatous / lymphomatous replacement depletion of bone marrow (chronic myelogenous leukemia, Hodgkin disease)

    • NO hematologic disease in 25%

  • absence of pain, bone erosion, calcification

  • chronic anemia

    Sites: in areas of fetal erythropoiesis

  • @ spleen

    • splenomegaly

    • focal isodense masses on enhanced CT

  • @ liver, lymph nodes

  • @ thorax: mediastinum, heart, thymus, lung

    • uni- / bilateral smooth lobulated paraspinal masses between T8 and T12

    • anterior rib ends expanded by masses

  • @ Spine

    • Most commonly afflicted in thalassemia

    • back pain, symptoms of spinal cord compression

    • coarsened trabeculation

    • extramedullary hematopoiesis in epidural space

  • @ adrenal glands

  • @ renal pelvis

  • @ gastrointestinal lymphatics

  • @ dura mater (falx cerebri and over brain convexity)

  • @ cartilage, broad ligaments

  • @ thrombi, adipose tissue

  • @ Bone marrow reconversion = conversion of fatty to hematopoietic marrow

    Sequence: vertebrae > flat bones of pelvis > long bones of extremities (proximal metaphysis > distal metaphysis > diaphysis)

  • lack of calcification / bone erosion

Familial Idiopathic Acroosteolysis

  • = HAJDU-CHENEY SYNDROME

  • = rare bizarre entity of unknown etiology

    Location: may be unilateral

  • fingernails remain intact

  • sensory changes + plantar ulcers rare

  • pseudoclubbing of fingers + toes with osteolysis of terminal + more proximal phalanges

  • genu varum / valgum

  • hypoplasia of proximal end of radius

  • subluxation of radial head

  • scaphocephaly, basilar impression

  • wide sutures, persistent metopic suture, Wormian bones, poorly developed sinuses

  • kyphoscoliosis

  • severe osteoporosis + fractures at multiple sites (esp. of spine)

  • protrusio acetabuli

Fanconi Anemia

  • = autosomal recessive disease with severe hypoplastic anemia + skin pigmentation + skeletal and urogenital anomalies

  • skin pigmentation (melanin deposits) in 74% (trunk, axilla, groin, neck)

  • anemia onset between 17 months and 22 years of age

  • bleeding tendency (pancytopenia)

  • hypogonadism (40%)

  • microphthalmia (20%)

  • anomalies of radial component of upper extremity (strongly suggestive):

    • absent / hypoplastic / supernumerary thumb

    • hypoplastic / absent radius

    • absent / hypoplastic navicular / greater multangular bone

  • slight / moderate dwarfism

  • minimal microcephaly

  • renal anomalies (30%): renal aplasia, ectopia, horseshoe kidney

Prognosis: fatal within 5 years after onset of anemia; patient's family shows high incidence of leukemia

Farber Disease

= DISSEMINATED LIPOGRANULOMATOSIS

Histo: foam cell granulomas; lipid storage of neuronal tissue (accumulation of ceramide + gangliosides)

  • hoarse weak cry

  • swelling of extremities; generalized joint swelling

  • subcutaneous + periarticular granulomas

  • intermittent fever, dyspnea

  • lymphadenopathy

  • capsular distension of multiple joints (hand, elbow, knee)

  • juxtaarticular bone erosions from soft-tissue granulomas

  • subluxation / dislocation

  • disuse / steroid deossification

Prognosis: death from respiratory failure within 2 years

Femoroacetabular impingement

= repetitive microtrauma due to an anatomic conflict between proximal femur + acetabular rim at extreme range of motion

Age: 2nd 3rd decade; in patients with increased sports activity

Femoroacetabular Impingement

P.77


Types:

  • Cam FAI

    • = nonspherical shape of femoral head with reduced depth of femoral waist leads to abutment of femoral head-neck junction against acetabular rim

    • osseous bump deforming femoral head-neck junction (50%)

    • a-angle of >55 (measured at the anterosuperior position on radial images rotated around center line of femoral neck)

    • cartilage lesions at anterosuperior acetabulum at posterior and posteroinferior acetabulum (pincer FAI)

  • Pincer FAI

    • = acetabular overcoverage limits range of motion

      Cause: protrusio acetabuli, acetabular retroversion

    • deep acetabulum (head center >5 mm below rim)

    • osseous bump deforming femoral head-neck junction (33%)

    • cartilage lesions at posterior and posteroinferior acetabulum (countercoup damage)

  • ossification of acetabular rim

  • separate bone fragment / os acetabuli

    Cx: premature osteoarthritis initially with cartilage damage + labral tears
    Rx: surgery in patients without osteoarthritis consisting of reshaping of femoral waist / trimming of acetabular rim / periacetabular osteotomy

Fibrochondrogenesis

= autosomal recessive lethal short-limb skeletal dysplasia

Incidence: 5 cases

  • severe micromelia + broad dumbbell-shaped metaphyses

  • flat + clefted pear-shaped vertebral bodies

  • short + cupped ribs

  • frontal bossing

  • low-set abnormally formed ears

Prognosis: stillbirth / death shortly after birth
DDx: (1) Thanatophoric dysplasia
(2) Metatropic dysplasia
(3) Spondyloepiphyseal dysplasia

Fibrodysplasia Ossificans Progressiva

  • = MYOSITIS OSSIFICANS PROGRESSIVA (misnomer since primarily connective tissues are affected)

  • = rare slowly progressive sporadic / autosomal dominant disease with variable penetrance characterized by remissions + exacerbations of fibroblastic proliferation, subsequent calcification + ossification of subcutaneous fat, skeletal muscle, tendons, aponeuroses, ligaments

Histo: edema with proliferating fibroblasts in a loose myxoid matrix; subsequent collagen deposition plus calcification + ossification of collagenized fibrous tissue in the center of nodules
Age: presenting by age 2 years (50%)

  • initially subcutaneous painful masses on neck, shoulders, upper extremities

  • progressive involvement of remaining musculature of back, chest, abdomen, lower extremities

  • lesions may ulcerate and bleed

  • muscles of back + proximal extremities become rigid followed by thoracic kyphosis

  • inanition secondary to jaw trismus (masseter, temporal muscle)

  • wry neck = torticollis (due to restriction of sternocleidomastoid muscle)

  • respiratory failure (thoracic muscles affected)

  • conductive hearing loss (fusion of middle ear ossicles)

  • ECTOPIC OSSIFICATION

    • rounded / linear calcification in neck / shoulders, paravertebral region, hips, proximal extremity, trunk, palmar + plantar fascia forming ossified bars + bony bridges

    • ossification of voluntary muscles, complete by 20 25 years (sparing of sphincters + head)

  • SKELETAL ANOMALIES

    • may appear before ectopic ossification

    • clinodactyly

    • microdactyly of big toes (90%) and thumbs (50%) = usually only one large phalanx present / synostosis of metacarpal + proximal phalanx (first sign)

    • phalangeal shortening of hand + foot (middle phalanx of 5th digit)

    • shortened 1st metatarsal + hallux valgus (75%)

    • shortened metacarpals + metatarsals

    • shallow acetabulum

    • short widened femoral neck

    • thickening of medial cortex of tibia

    • progressive fusion of posterior arches of cervical spine

    • narrowed AP diameter of cervical + lumbar vertebral bodies

    • bony ankylosis

CAVE: surgery is hazardous causing accelerated ossification at the surgical site

Fibroma of Soft Tissue

Histo: hypocellular highly collagenic tumor
Age: 3rd and 4th decades; M > F
Location: tendon sheath of distal upper extremity

  • slowly growing lesion 1 5 cm in size

  • MR:

    • small hypointense nodule on all pulse sequences

Fibrosarcoma

Incidence: 4% of all primary bone neoplasm

Etiology:

  • PRIMARY FIBROSARCOMA (70%)

  • SECONDARY FIBROSARCOMA (30%)

    • following radiotherapy of giant cell tumor / lymphoma / breast cancer

      • P.78


    • underlying benign lesion: Paget disease (common); giant cell tumor, bone infarct, osteomyelitis, desmoplastic fibroma, enchondroma, fibrous dysplasia (rare)

    • dedifferentiation of low-grade chondrosarcoma

Histo: spectrum of well to poorly differentiated fibrous tissue proliferation; will not produce osteoid / chondroid / osseous matrix
Age: predominantly in 3rd 5th decade (range of 8 88 years); M:F = 1:1
Metastases to: lung, lymph nodes

  • localized painful mass

Location: tubular bones in young, flat bones in older patients; femur (40%), tibia (16%) (about knee in 30 50%), jaw, pelvis (9%); rare in small bones of hand + feet or spinal column
Site: eccentric at diaphyseal-metaphyseal junction into metaphysis; intramedullary / periosteal

  • CENTRAL FIBROSARCOMA

    • = intramedullary

    • well-defined lucent bone lesion

    • thin expanded cortex

    • aggressive osteolysis with geographic / ragged / permeative bone destruction + wide zone of transition

    • occasionally large osteolytic lesion with cortical destruction, periosteal reaction + soft-tissue invasion

    • sequestration of bone may be present (DDx: eosinophilic granuloma, bacterial granuloma)

    • sparse periosteal proliferation (uncommon)

    • intramedullary discontinuous spread

    • no calcification

      DDx: malignant fibrous histiocytoma, myeloma, telangiectatic osteosarcoma, lymphoma, desmoplastic fibroma, osteolytic metastasis

  • PERIOSTEAL FIBROSARCOMA

    • = rare tumor arising from periosteal connective tissue

      Location: long bones of lower extremity, jaw

    • contour irregularity of cortical border

    • periosteal reaction with perpendicular bone formation may be present

    • rarely extension into medullary cavity

Cx: pathologic fracture (uncommon)
Prognosis: 20% 10-year survival
DDx: (1) Osteolytic osteosarcoma (2nd 3rd decade)
(2) Chondrosarcoma (usually contains characteristic calcifications)
(3) Aneurysmal bone cyst (eccentric blown-out appearance with rapid progression)
(4) Malignant giant cell tumor (begins in metaphysis extending toward joint)

Fibrous Cortical Defect

Incidence: 30% of children; M:F = 2:1
Age: peak age of 7 8 years (range of 2 10 years); mostly before epiphyseal closure
Histo: fibrous tissue from periosteum invading underlying cortex

  • asymptomatic

Location: metaphyseal cortex of long bone; posterior medial aspect of distal femur, proximal tibia, proximal femur, proximal humerus, ribs, ilium, fibula

  • round when small, average diameter of 1 2 cm

  • oval, extending parallel to long axis of host bone

  • cortical thinning + expansion may occur

  • smooth, well-defined / scalloped margins

  • larger lesions are multilocular

  • involution over 2 4 years

Prognosis:

  • potential to grow and encroach on the medullary cavity leading to nonossifying fibroma

  • bone islands in the adult may be residue of incompletely involuted cortical defect

Fibrous Dysplasia

  • = FIBROUS OSTEODYSTROPHY = OSTEODYSTROPHIA FIBROSA = OSTEITIS FIBROSA DISSEMINATA = LICHTENSTEIN-JAFF DISEASE

  • = benign fibroosseous developmental anomaly of the mesenchymal precursor of bone, manifested as a defect in osteoblastic differentiation and maturation

Cause: probable gene mutation during embryogenesis
Age: 1st 2nd decade (highest incidence between 3 and 15 years), 75% before age 30; progresses until growth ceases; M:F = 1:1
Path: spongiosa of medullary cavity filled by abnormal fibrous tissue containing poorly calcified trabeculae
Histo: matrix of immature collagen contains small irregularly shaped trabeculae of immature, inadequately mineralized woven bone; trabeculae not rimmed by osteoblasts (DDx from ossifying fibroma); cartilaginous islands present in 10% (DDx: chondrosarcoma)

Clinical Types:

  • MONOSTOTIC FORM (70 80%)

    • usually asymptomatic until 2nd 3rd decade

      Location: ribs (28%), proximal femur (23%), tibia, craniofacial bones (10 25%), humerus

  • POLYOSTOTIC FORM (20 30%)

    Age: mean age of 8 years

    • 2/3 symptomatic by age 10

    • leg pain, limp, pathologic fracture (75%)

    • abnormal vaginal bleeding (25%)

    • coast of Maine caf -au-lait spots = few yellowish to brownish dark patches of cutaneous pigmentation with irregular / serrated border, predominantly on back of trunk (30 50%), buttocks, neck, shoulders; often ipsilateral to bone lesions (DDx: more numerous and lighter coast of California spots of neurofibromatosis)

      Associated with: endocrinopathy (in 2 3%)
      Location: usually unilateral + asymmetric; femur (91%), tibia (81%), pelvis (78%), foot (73%), ribs, skull + facial bones (50%), upper extremities, lumbar spine (14%), clavicle (10%), cervical spine (7%)
      Site: metadiaphysis

    • leg length discrepancy (70%)

    • shepherd's crook deformity (35%)

    • facial asymmetry

    • tibial bowing

    • rib deformity

    • ray pattern = involvement of all phalanges + metacarpal bone of a single digit

    • P.79


  • CRANIOFACIAL FORM = LEONTIASIS OSSEA

    Incidence: in 10 25% of monostotic form / in 50% of polyostotic form / isolated

    • cranial asymmetry

    • facial deformity

    • nasal stuffiness

    • proptosis

    • visual impairment / unilateral blindness

      Location: sphenoid, frontal, maxillary, ethmoid bones > occipital, temporal bones

    • unilateral overgrowth of facial bones + calvarium (NO extracranial lesions)

    • outward expansion of outer table maintaining convexity (DDx: Paget disease with destruction of inner + outer table)

    • prominence of external occipital protuberance

      Cx: neurologic deficit secondary to narrowed cranial foramina (eg, blindness)

  • CHERUBISM (special variant)

    • = FAMILIAL FIBROUS DYSPLASIA

    • = autosomal dominant disorder of variable penetrance

      Age: childhood; more severe in males

    • bilateral jaw fullness + slight upward turning of eyes

    • bilateral expansile multiloculated cystic masses with symmetric involvement of mandible + maxilla

      Cx: problems with dentition after perforation of cortex
      Prognosis: regression after adolescence

May be associated with:

  • endocrine disorders:

    • precocious puberty in girls

    • hyperthyroidism

    • hyperparathyroidism: renal stones, calcinosis

    • acromegaly

    • diabetes mellitus

    • Cushing syndrome: osteoporosis, acne

    • growth retardation

  • soft-tissue myxoma (rare) = Mazabraud syndrome: typically multiple intramuscular lesions in vicinity of most severely affected bone

VARIANT: McCune-Albright syndrome (10%)
Sex: almost exclusively in girls

  • polyostotic unilateral fibrous dysplasia

  • coast of Maine caf -au-lait spots (35%)

  • endocrinopathy: peripheral sexual precocity (menarche in infancy [20%]), hyperthyroidism

    • swelling + tenderness

    • limp, pain ( pathologic fracture)

    • increased alkaline phosphatase

    • advanced skeletal + somatic maturation (early)

    Common location: rib cage (30%), craniofacial bones [calvarium, mandible] (25%), femoral neck + tibia (25%), pelvis
    Site: metaphysis is primary site with extension into diaphysis (rarely entire length)

    • normal bone architecture altered + remodeled

    • lesions in medullary cavity: radiolucent / ground-glass appearance / increased density

    • trabeculated appearance due to reinforced subperiosteal bone ridges in wall of lesion

    • expansion of cortices (ribs, skull, long bones) with blown-out appearance

    • well-defined sclerotic margin of reactive bone = rind

    • endosteal scalloping with thinned / lost cortex (ribs, long bones) and intervening normal cortex is HALLMARK

    • lesion may undergo calcification + enchondral bone formation = fibrocartilaginous dysplasia

    • increased activity on bone scan during early perfusion + on delayed images

    CT:

    • Most cases of monostotic fibrous dysplasia are incidental findings on a cranial CT examination!

    • ground-glass lucencies

    • sclerotic margins + well-defined borders

    • expansion of bone

    MR:

    • MRI should not be used to differentiate fibrous dysplasia from other entities due to the extreme variability in the appearance of the bone lesions!

    • homogeneous / mildly heterogeneous marrow lesions hyperintense to fat (60%) / of intermediate / of low signal intensity on T2WI

    • marrow lesions hypointense to muscle on T1WI

    NUC:

    • increased tracer uptake on bone scans (lesions remain metabolically active into adulthood)

    • @ Skull

      • skull deformity with cranial nerve compromise

      • proptosis

      Location: frontal bone > sphenoid bone; hemicranial involvement (DDx: Paget disease is bilateral)

      • blistering / bubbling cystic calvarial lesions (CHARACTERISTIC), commonly crossing sutures

      • sclerotic skull base, may narrow neural foramina (visual + hearing loss)

      • widened diploic space with displacement of outer table, inner table spared (DDx: Paget disease, inner table involved)

      • obliteration of sphenoid + frontal sinuses due to encroachment by fibrous dysplastic bone

      • inferolateral displacement of orbit

      • sclerosis of orbital plate + small orbit + hypoplasia of frontal sinuses (DDx: Paget disease, meningioma en plaque)

      • occipital thickening

      • mandibular cystic lesion (very common) = osteocementoma, ossifying fibroma

    • @ Pelvis + ribs

      • bubbly cystic lesions (extremely common)

      • fusiform enlargement of ribs + loss of normal trabecular pattern + thin preserved cortex (in up to 30%)

        • Fibrous dysplasia is the most common cause of a benign expansile lesion of a rib!

        • A rib is the most common site of monostotic fibrous dysplasia!

      • protrusio acetabuli

    • @ Extremities

      • short stature as adult / dwarfism

      • premature fusion of ossification centers

      • epiphysis rarely affected before closure of growth plate

        • P.80


      • bowing deformities + discrepant limb length (tibia, femur) due to stress of normal weight bearing

      • shepherd's crook deformity of femoral neck = coxa vara

      • pseudarthrosis in infancy = osteofibrous dysplasia (DDx: neurofibromatosis)

      • premature onset of arthritis

    Cx: (1) Dedifferentiation into osteo- / fibro- / (rarely) chondrosarcoma or malignant fibrous histiocytoma (0.5 1%, more often in polyostotic form)
    increasing pain
    enlarging soft-tissue mass
    previously mineralized lesion turns lytic
    (2) Pathologic fractures: transformation of woven into lamellar bone may be seen, subperiosteal healing without endosteal healing

    DDx:

    • Paget disease (mosaic pattern histologically, radiographically similar to monostotic cranial lesion, outer table involved, sparing of facial bones)

    • Neurofibromatosis (rarely osseous lesions, vertebral column is primary target, ribbon ribs, cystic intraosseous neurofibroma rare, caf -au-lait spots smooth, familial disease)

    • HPT (principally histologic problem, chemical changes, generalized deossification, subperiosteal resorption)

    • Osteofibrous dysplasia (almost exclusively in tibia of children <10 years + anterior bowing, monostotic, lesion begins in cortex, spontaneous regression)

    • Nonossifying fibroma

    • Simple bone cyst

    • Giant cell tumor (no sclerotic margin)

    • Enchondromatosis

    • Eosinophilic granuloma (beveled margin in skull, black hole on CT of lower density)

    • Osteoblastoma

    • Hemangioma

    • Meningioma

    Prognosis: bone lesions usually do not progress beyond puberty

Fibrous Histiocytoma

Benign Fibrous Histiocytoma

Incidence: 0.1% of all bone tumors
Histo: interlacing bundles of fibrous tissue in storiform pattern (whorled / woven) interspersed with mono- / multinucleated cells resembling histiocytes, benign giant cells, and lipid-laden macrophages; resembles nonossifying fibroma / fibroxanthoma
Age: 23 60 years

  • localized intermittently painful soft-tissue swelling

Location: long bone, pelvis, vertebra (rare)
Site: typically in epiphysis / epiphyseal equivalent

  • well-defined radiolucent lesion with septa / soap-bubble appearance / no definable matrix

  • may have reactive sclerotic rim

  • narrow transition zone (= nonaggressive lesion)

  • no periosteal reaction

Rx: curettage
DDx: nonossifying fibroma (childhood / adolescence, asymptomatic, eccentric metaphyseal location)

Atypical Benign Fibrous Histiocytoma

Histo: atypical aggressive features = mitotic figures present

  • lytic defect with irregular edges

Prognosis: may metastasize

Malignant Fibrous Histiocytoma

= MFH = MALIGNANT FIBROUS XANTHOMA = XANTHO-SARCOMA = MALIGNANT HISTIOCYTOMA = FIBRO-SARCOMA VARIANT

Histo: spindle-cell neoplasm of a mixture of fibroblasts + giant cells resembling histiocytes with nuclear atypia and pleomorphism in pinwheel arrangement; closely resembles high-grade fibrosarcoma (= fibroblastic cells arranged in uniform pattern separated by collagen fibers)
(a) pleomorphic-storiform subtype (50 60%)
(b) myxoid subtype (25%)
(c) giant cell subtype (5 10%)
(d) inflammatory subtype (5 10%)
(e) angiomatoid subtype (<5%)
Age: 10 90 (average 50) years; peak prevalence in 5th decade; more frequent in Caucasians; M:F = 3:2
Location: potential to arise in any organ (ubiquitous mesenchymal tissue); soft tissues >> bone

Soft-tissue MFH

Incidence: 20 30% of all soft-tissue sarcomas; most common primary malignant soft-tissue tumor of late adult life

  • Any deep-seated invasive intramuscular mass in a patient >50 years of age is most likely MFH!

Location: extremities (75%), [lower extremity (50%), upper extremity (25%)], retroperitoneum (15%), head + neck (5%)
Site: within large muscle groups

  • large painless soft-tissue mass with progressive enlargement over several months

  • mass usually 5 10 cm in size with increase over months / years

  • poorly defined curvilinear / punctate peripheral calcifications / ossifications (in 5 20%)

  • cortical erosion of adjacent bone (HIGHLY SUGGESTIVE FEATURE)

  • CT:

    • well-defined soft-tissue mass with central hypodense area = myxoid MFH (DDx: hemorrhage, necrosis, leiomyosarcoma with necrosis, myxoid lipo- / chondrosarcoma)

    • enhancement of solid components

  • MR:

    • inhomogeneous poorly defined lesion iso- / hyperintense to muscle on T1WI + hyperintense on T2WI

Prognosis: larger + more deeply located tumors have a worse prognosis; 2-year survival rate of 60%; 5-year survival rate of 50%; local recurrence rate of 44%; metastatic rate of 42% (lung, lymph nodes, liver, bone)
DDx: (1) Liposarcoma (younger patient, presence of fat in >40%, calcifications rare)
(2) Rhabdomyosarcoma
(3) Synovial sarcoma (cortical erosion)

P.81


Osseous MFH

Prevalence: 5% of all primary malignant bone tumors

  • painful, tender, rapidly enlarging mass

  • pathologic fracture (20%)

Associated with: prior radiation therapy, bone infarcts, Paget disease, fibrous dysplasia, osteonecrosis, fibroxanthoma (= nonossifying fibroma), enchondroma, chronic osteomyelitis

  • 20% of all osseous MFH arise in areas of abnormal bone!

Location: femur (45%), tibia (20%), 50% about knee; humerus (10%); ilium (10%); spine; sternum; clavicle; rarely small bones of hand + feet
Site: central metaphysis of long bones (90%); eccentric in diaphysis of long bones (10%)

  • radiolucent defect with ill-defined margins (2.5 10 cm in diameter)

  • extensive mineralization / small areas of focal metaplastic calcification

  • permeation + cortical destruction

  • expansion in smaller bones (ribs, sternum, fibula, clavicle)

  • occasionally lamellated periosteal reaction (especially in presence of pathologic fracture)

  • soft-tissue extension

Cx: pathologic fracture (30 50%)
DDx: (1) Metastasis
(2) Fibrosarcoma (often with sequestrum)
(3) Reticulum cell sarcoma
(4) Osteosarcoma
(5) Giant cell tumor
(6) Plasmacytoma

Pulmonary MFH (extremely rare)

  • solitary pulmonary nodule without calcification

  • diffuse infiltrate

  • NUC:

    • increased uptake of Tc-99m MDP (mechanism not understood)

    • increased uptake of Ga-67 citrate

  • US:

    • well-defined mass with hyperechoic + hypoechoic (necrotic) areas

  • CT:

    • mass of muscle density with hypodense areas (necrosis)

    • invasion of abdominal musculature, but not IVC / renal veins (DDx to renal cell carcinoma)

  • Angio:

    • hypervascularity + early venous return

Focal Fibrocartilaginous Dysplasia of Tibia

Associated with: tibia vara
Age: 9 28 months
Histo: dense hypocellular fibrous tissue resembling tendon with lacuna formation

  • slight shortening of affected leg

Location: insertion of pes anserinus (= tendinous insertion of gracilis, sartorius, semitendinosus muscles) distal to proximal tibial physis; unilateral involvement

  • unilateral tibia vara

  • well-defined elliptic obliquely oriented lucent defect in medial tibial metadiaphyseal cortex

  • sclerosis along lateral border of lesion

  • absence of bone margin superomedially

Prognosis: resolution in 1 4 years
DDx: (1) Unilateral Blount disease (typically bilateral in infants, varus angulation of upper tibia, decreased height of medial tibial metaphysis, irregular physis)
(2) Chondromyxoid fibroma, eosinophilic granuloma, osteoid osteoma, osteoma, fibroma, chondroma (not associated with tibia vara, soft-tissue mass)

Fracture

= soft-tissue injury in which there is a break in the continuity of bone or cartilage

General description:

  • OPEN / [CLOSED]

    open Fx = communication between fractured bone + skin

  • [COMPLETE]/INCOMPLETE

    complete Fx = all cortical surfaces disrupted
    incomplete Fx = partial separation of bone
    greenstick Fx = break of one cortical margin only with intact periosteum due to tension on soft growing bone
    buckle / torus Fx = buckling of cortex due to compression
    bowing Fx = plastic deformity of thin long bone (clavicle, ulna, fibula)
    lead-pipe Fx = combination of greenstick + torus Fx

  • SIMPLE / COMMINUTED

    simple Fx = noncomminuted
    comminuted Fx = >2 fragments
    segmental Fx = isolated segment of shaft
    butterfly fragment = V-shaped fragment not completely circumscribed by cortex

  • DIRECTION OF FRACTURE LINE in relation to long axis of bone: transverse, oblique, oblique-transverse, spiral

Special terminology:

avulsion Fx = fragment pulled off by tendon / ligament from parent bone
transchondral Fx = cartilaginous surface involved
chondral Fx = cartilage alone involved
osteochondral Fx = cartilage + subjacent bone involved

Description of anatomic positional changes:

  • = change in position of distal fracture fragment in relation to proximal fracture fragment

  • LENGTH

    • = longitudinal change of fragments

    • distraction = increase from original anatomic length

    • shortening = decrease from original anatomic length

    • impacted = fragments driven into each other

    • overriding = also includes latitudinal changes

    • overlapping = bayonet apposition

    • P.82


  • DISPLACEMENT

    • = latitudinal change of anatomic axis:

    • undisplaced

    • anterior, posterior, medial / ulnar, lateral / radial

  • ANGULATION / TILT

    • = long axes of fragments intersect at the fracture apex:

    • medial / lateral, ventral / dorsal

    • varus = angular deviation of distal fragment toward midline on frontal projection

    • valgus = angular deviation of distal fragment away from midline on frontal projection

    • eg, ventral angulation of fracture apex

    • eg, in anatomic / near anatomic alignment

  • ROTATION

    • Difficult to detect radiographically!

    • differences in diameters of apposing fragments

    • mismatch of fracture line geometry

    • internal / external rotation

NUC:

  • Typical time course:

    • Acute phase (3 4 weeks)

      • abnormal in 80% <24 hours, in 95% <72 hours

      • Elderly patients show delayed appearance of positive scan

      • broad area of increased tracer uptake (wider than fracture line)

    • Subacute phase (2 3 months) = time of most intense tracer accumulation

      • more focal increased tracer uptake corresponding to fracture line

    • Chronic phase (1 2 years)

      • slow decline in tracer accumulation

      • in 65% normal after 1 year; >95% normal after 3 years

  • Return to normal:

    • Non weight-bearing bone returns to normal more quickly than weight-bearing bone

    • Rib fractures return to normal most rapidly

    • Complicated fractures with orthopedic fixation devices take longest to return to normal

    • Simple fractures: 90% normal by 2 years

    • Open reduction / fixation: <50% normal by 3 years

    • Delayed union: slower than normal for type of fracture

    • Nonunion: persistent intense uptake in 80%

    • Complicated union (true pseudarthrosis, soft-tissue interposition, impaired blood supply, presence of infection)

      • intense uptake at fracture ends

      • decreased uptake at fracture site

    • Vertebral compression fractures: 60% normal by 1 year; 90% by 2 years; 97% by 3 years

Pathologic Fracture

= fracture at site of preexisting osseous abnormality

Cause: tumor, osteoporosis, infection, metabolic disorder

Stress Fracture

= fractures produced as a result of repetitive prolonged muscular action on bone that has not accommodated itself to such action

Insufficiency Stress Fracture

= normal physiologic stress applied to bone with abnormal elastic resistance / deficient mineralization

Cause:

  • Osteoporosis

  • Renal osteodystrophy

  • Osteomalacia / rickets

  • Hyperparathyroidism

  • Radiation therapy

  • Rheumatoid arthritis

  • Paget disease

  • Fibrous dysplasia

  • Osteogenesis imperfecta

  • Osteopetrosis

  • Prolonged corticosteroid treatment

  • Tumor treatment with ifosfamide, methotrexate

Location: thoracic vertebra, sacrum, pubic bone, ilium, lower extremity (calcaneus, tibia, fibula)
Fracture orientation: perpendicular to long axis of bone

Plain film / CT (1 2 weeks after onset of fracture):

  • cortical lucency (due to disruption)

  • periosteal new bone formation

  • medullary sclerosis (endosteal callus formation)

MR:

  • zone of low signal intensity on T1WI + variable intensity on T2WI (= discrete fracture line)

  • surrounded by diffuse marrow edema (hypointense on T1WI + hyperintense)

  • hyperintense components of circumferential periosteal reaction + early callus + surrounding edema adjacent to bone on T2WI with enhancement after IV Gd-chelate (DDx: osteomyelitis with more eccentric involvement)

NUC (bone scan):

  • increased abnormal uptake

Pelvic Insufficiency Stress Fracture

  • severe pain in lower back + sacroiliac joints; radiates to buttocks, hips, groin, legs; worsens with weight bearing

  • walking ability impaired

Incidence: 1.8 5% of women >55 years
Predisposed: postmenopausal women
Location: sacral ala, parasymphyseal region of os pubis, pubic rami, supraacetabular region, iliac blades, superomedial portion of ilium

Types:

  • occult fracture:

    Site: sacrum > supraacetabulum, ilium

    • sclerotic band, cortical disruption, fracture line

    • Often obscured by overlying bowel gas + osteopenia!

      Types of Fractures

      Type Bone Quality Load
      Traumatic normal single large
      Fatigue (stress) normal repetitive
      Insufficiency (stress) abnormal (metabolic) minimal
      Pathologic abnormal (tumor) minimal

      Fatigue (Stress) and insufficiency fracture of Hip

    • P.83


  • aggressive fracture:

    Site: parasymphysis, pubic rami

    • exuberant callus formation, osteolysis + fragments (with prolonged or delayed healing / chronic nonunion)

    CAVE: fracture may be misdiagnosed as neoplasm; interpretation also histologically difficult

NUC:

  • butterfly / H-shaped ( Honda sign ) / asymmetric incomplete H-shaped pattern of sacral uptake

  • pelvic outlet view for parasymphyseal fx

CT and MR (most accurate modalities):

  • sclerotic band, linear fracture line, cortical disruption, fragmentation, displacement

  • bone marrow edema

  • Excludes bone destruction + soft-tissue masses!

Prognosis: healing in 12 30 months

Femoral Insufficiency Fracture

Site: subcapital

  • subtle femoral neck angulation

  • trabecular angulation

  • subcapital impaction line

Fatigue Stress Fracture

  • = normal bone subjected to repetitive stresses (none of which is singularly capable of producing a fracture) leading to mechanical failure over time

    Risk factors: new / different / rigorous repetitive activity; female sex; increased age; Caucasian race; low bone mineral density; low calcium intake; fluoride treatment for osteoporosis; condition resulting in altered gait

  • activity-related pain abating with rest

  • constant pain with continued activity

  • @ Spine

    • Clay shoveler's fracture: spinous process of lower cervical / upper thoracic spine

    • Spondylolysis = pars interarticularis of lumbar vertebrae: ballet, lifting heavy objects, scrubbing floors

    • Ribs: carrying heavy pack, golf, coughing

  • @ Upper extremity

    • Clavicle: postoperative (radical neck dissection)

    • Coracoid process of scapula: trap shooting

    • Coronoid process of ulna: pitching ball, throwing javelin, pitchfork work, propelling wheelchairs

    • Distal shaft of humerus: throwing ball

    • Hook of hamate: swinging golf club / tennis racquet / baseball bat

  • @ Pelvis

    • Obturator ring of pelvis: stooping, bowling, gymnastics

      Site: superior / inferior pubic ramus

    • Sacrum (<2%): long-distance runner, military recruits

      Site: unilateral (? due to leg length discrepancy)

  • @ Lower extremity

    • Femoral neck: ballet, long-distance running

      Site: medial femoral neck

      • subtle lucency / sclerosis (= acute fracture)

      • lucent line surrounded by sclerosis (= subacute fracture)

    • Femoral shaft: ballet, marching, long-distance running, gymnastics

    • Patella: hurdling

    • Tibial shaft: ballet, jogging

    • Fibula: long-distance running, jumping, parachuting

  • @ Foot (in order of frequency):

    • Second metatarsal: marching, stomping on ground, prolonged standing, ballet, postoperative bunionectomy

    • Calcaneus: jumping, parachuting, prolonged standing, recent immobilization

      • vertical / oblique fracture orientation anterior to tuberosity

    • Navicular: stomping on ground, marching, prolonged standing, ballet

      • vertically oriented fracture in midbody

      • Midfoot fractures are difficult to diagnose by conventional radiography; CT + MRI are often helpful

    • Sesamoids of metatarsal: prolonged standing

X-RAY (15% sensitive in early fractures, increasing to 50% on follow-up):

  • cancellous (trabecular) bone (notoriously difficult to detect)

    • subtle blurring of trabecular margins

    • faint sclerotic radiopaque area of peritrabecular callus (50% change in bone density needed)

    • sclerotic band (due to trabecular compression + callus formation) usually perpendicular to cortex

  • compact (cortical) bone

    • gray cortex sign = subtle ill definition of cortex

    • intracortical radiolucent striations (early)

    • solid thick lamellar periosteal new bone formation

    • endosteal thickening (later)

  • Follow-up radiography after 2 3 weeks of conservative therapy

    Salter-Harris Classification of Epiphyseal Plate injury

    Rang and Ogden's additions to Salter-Harris Classification

P.84


NUC ( gold standard = almost 100% sensitive):

  • abnormal uptake within 6 72 hours of injury (prior to radiographic abnormality)

  • stress reaction = focus of subtly increased uptake

  • focal fusiform area of intense cortical uptake

  • abnormal uptake persists for months

MR (very sensitive modality; fat saturation technique most sensitive as it detects an increase in water content of medullary edema / hemorrhage):

  • diminished marrow signal intensity on T1WI of fracture line

  • increased marrow signal intensity on T2WI (edema may obscure the fracture line), resolves within 6 months in 90%

  • low-intensity band contiguous with cortex on T2WI = fracture line of more advanced lesion

CT (least sensitive modality):

helpful in: longitudinal stress fracture of tibia; in confusing pediatric stress fracture (to detect endosteal bone formation)

DDx:

  • Shin splints (activity not increased in angiographic / blood-pool phase)

    • long linear uptake on posteromedial (soleus muscle) / anterolateral (tibialis anterior muscle) tibial cortex on delayed images (from stress to periosteum at muscle insertion site)

  • Osteoid osteoma (eccentric, nidus, solid periosteal reaction, night pain)

  • Chronic sclerosing osteomyelitis (dense, sclerotic, involving entire circumference, little change on serial radiographs)

  • Osteomalacia (bowed long bones, looser zones, gross fractures, demineralization)

  • Osteogenic sarcoma (metaphyseal, aggressive periosteal reaction)

  • Ewing tumor (lytic destructive appearance with soft-tissue component, little change on serial radiographs)

Epiphyseal Plate Injury

Prevalence: 6 18 30% of bone injuries in children <16 years of age
Peak age: 12 years
Location: distal radius (28%), phalanges of hand (26%), distal tibia (10%), distal phalanges of foot (7%), distal humerus (7%), distal ulna (4%), proximal radius (4%), metacarpals (4%), distal fibula (3%)
Mechanism: 80% shearing force; 20% compression
Resistance to trauma: ligament > bone > physis (hypertrophic zone most vulnerable)

Salter-Harris classification (considering probability of growth disturbance)

  • [Robert Bruce Salter (1924 ) and W. Robert Harris (1922 ), orthopedic surgeons in Toronto, Canada]

  • Prognosis is worse in lower extremities (ankle + knee) irrespective of Salter-Harris type!

mnemonic: SALTR
Slip of physis = type 1
Above physis = type 2
Lower than physis = type 3
Through physis = type 4
Rammed physis = type 5

P.85


Salter Type 1 (6 8.5%)

  • = slip of epiphysis due to shearing force separating epiphysis from physis

    Line of cleavage: confined to physis
    Location: most commonly in phalanges, distal radius (includes: apophyseal avulsion, slipped capital femoral epiphysis)

  • displacement of epiphyseal ossification center

    Prognosis: favorable irrespective of location

Salter Type 2 (73 75%)

= shearing force splits growth plate

Line of fracture: through physis + extending through margin of metaphysis separating a triangular metaphyseal fragment (= corner sign )
Location: distal radius (33 50%), distal tibia + fibula, phalanges
Prognosis: good, may result in minimal shortening

Salter Type 3 (6.5 8%)

  • = intraarticular fracture, often occurring after partial closure of physis

    Line of fracture: vertically / obliquely through epiphysis + extending horizontally to periphery of physis
    Location: distal tibia, distal phalanx, rarely distal femur

  • epiphysis split vertically

    Prognosis: fair (imprecise reduction leads to alteration in linearity of articular plane)

Salter Type 4 (10 12%)

Location: lateral condyle of humerus, distal tibia

  • fracture involves metaphysis + physis + epiphysis

    Prognosis: guarded (may result in deformity + angulation)

Salter Type 5 (<1%)

  • = crush injury with injury to vascular supply

    Location: distal femur, proximal tibia, distal tibia
    Often associated with: fracture of adjacent shaft

  • no immediate radiographic finding

  • shortening of bone + cone epiphysis / angular deformity on follow-up

    Prognosis: poor (impairment of growth in 100%)

Triplane Fracture (6%)

Location: distal tibia, lateral condyle of distal humerus

  • vertical fracture of epiphysis + horizontal cleavage plane within physis + oblique fracture of adjacent metaphysis

  • MR:

    • focal dark linear area (= line of cleavage) within bright physis on gradient echo images (GRE)

    Cx: (1) progressive angular deformity from segmental arrest of germinal zone growth with formation of a bone bridge across physis = bone bar
    (2) limb length discrepancy from total cessation of growth
    (3) articular incongruity from disruption of articular surface
    (4) Bone infarction in metaphysis / epiphysis

Apophyseal Injury

Mechanism: excessive avulsive force

  • Physis under secondary ossification center is weakest part!

    At risk: young athletes: hurdlers, sprinters, cheerleaders (repetitive to and fro adduction / abduction + flexion / extension)
    Age: children > adults
    Avulsion injury of lesser trochanter in adults suggests underlying malignant disease

  • pain, point tenderness, swelling

  • irregularity at site of avulsion

  • displaced pieces of bone of variable size:

    • crescentic ossific opacity if viewed on tangent

    • very subtle disk-shaped opacity if seen en face

    abnormal foci of heterotopic ossification (later)

  • prominent bone formation in chronic avulsion injury from overuse with repeated microtraumas

DDx of healing acute injury: osteomyelitis, Ewing sarcoma

Hand Fracture

Bennett Fracture

  • [Edward Hallaran Bennett (1837 1907), surgeon in Dublin, Ireland]

    Mechanism: forced abduction of thumb

  • intraarticular fracture-dislocation of base of 1st metacarpal

  • small fragment of 1st metacarpal continues to articulate with trapezium

  • lateral retraction of 1st metacarpal shaft by abductor pollicis longus

Rx: anatomic reduction important, difficult to keep in anatomic alignment
Cx: pseudarthrosis

Boxer's Fracture

Mechanism: direct blow with clenched fist

  • transverse fracture of distal metacarpal (usually 5th)

Gamekeeper's Thumb

= SKIER'S THUMB (originally described as chronic lesion in hunters strangling rabbits)

P.86


Incidence: 6% of all skiing injuries; 50% of skiing injuries to the hand
Mechanism: violent abduction of thumb with injury to ulnar collateral ligament (UCL) in 1st MCP (faulty handling of ski pole)

Apophyseal Avulsion Injuries

Location Muscle Origin / Insertion
Anterior superior iliac spine sartorius muscle + tensor fasciae latae m.
Anterior inferior iliac spine rectus femoris muscle
Lesser trochanter iliopsoas muscle
Ischial tuberosity hamstrings
Greater trochanter gluteus medius + minimus, internal obturator, gemellus, piriformis
Iliac crest abdominal musculature
Symphysis pubis + inferior pubic ramus long + short adductors, gracilis

No Caption Available.

  • disruption of ulnar collateral ligament of 1st MCP joint, usually occurring distally near insertion on proximal phalanx

  • radial stress examination necessary to document ligamentous disruption

  • displacement of UCL superficial to aponeurosis of adductor pollicis (= Stener lesion) [torn end of UCL may be marked by avulsed bone fragment]

Navicular Fracture

  • = SCAPHOID FRACTURE

  • Most frequent (90%) of all carpal bones fractures!

    Mechanism: fall on dorsiflexed outstretched hand

  • pain + tenderness at anatomic snuff box

    Radiographic misses: 25 33 65%
    N.B.: If initial radiograph negative, reexamine in 2 + 6 weeks after treatment with short-arm spica cast!

  • MR: high sensitivity

    Bone scan: up to 100% sensitive, 93% PPV after 2 3 days
    Prognosis: dependent on following factors

    • fracture displacement = >1 mm offset / angulation / rotation of fragments (less favorable)

    • location (blood supply derived from distal part):

      • distal 1/3 (10%) = usually fragments reunite

      • middle 1/3 (70%) = failure to reunite in 30%

      • proximal 1/3 (20%) = failure to reunite in 90%

    • orientation of fracture

      • transverse / horizontal oblique = relatively stable

      • vertical oblique (less common) = unstable

    • Good prognosis with distal fracture + no displacement + no ligamentous injury!

    • Less favorable prognosis with displaced / comminuted fracture + proximal pole fracture!

    Cx: avascular necrosis of proximal fragment

Rolando Fracture

  • [Silvio Rolando (? 1931?), surgeon in Genoa, Italy]

  • comminuted Y- / T-shaped intraarticular fracture-dislocation through base of thumb metacarpal

Prognosis: worse than Bennett's fracture (difficult to reduce)

No Caption Available.

Forearm Fracture

Barton Fracture

  • [John Rhea Barton (1794 1871), orthopedic surgeon at Pennsylvania Hospital, Philadelphia]

    Mechanism: fall on outstretched hand

    • P.87


  • intraarticular oblique fracture of ventral / dorsal lip of distal radius

  • carpus dislocates with distal fragment up and back on radius

Chauffeur Fracture

  • = HUTCHINSON FRACTURE = BACKFIRE FRACTURE = LORRY DRIVER FRACTURE

    [Jonathan Hutchinson (1828 1913), British surgeon]

  • = name derived from direct trauma to radial side of wrist sustained from recoil of crank used in era of hand cranking to start automobiles

    Mechanism: acute dorsiflexion + abduction of hand

  • triangular fracture of radial styloid process

Colles Fracture

  • [Abraham Colles (1773 1843), surgeon in Dublin, Ireland]

  • = POUTEAU FRACTURE (term used in France)

  • [Claude Pouteau (1725 1775), surgeon in Lyon, France]

  • Most common fracture of forearm!

Mechanism: fall on outstretched hand

  • nonarticular radial fracture in distal 2 cm

  • dorsal displacement of distal fragment + volar angulation of fracture apex

  • ulnar styloid fracture

  • silver-fork deformity

    Cx: posttraumatic arthritis
    Rx: anatomic reduction important

  • Significant postreduction deformity:

    • Residual positive ulnar variance >5 mm indicates unsatisfactory outcome in 40%

    • Dorsal angulation of palmar tilt >15 decreases grip strength + endurance in >50%

Essex-Lopresti Fracture

  • [Peter Gordon Essex-Lopresti (1918 1951), surgeon at Birmingham Accident Center, England]

  • comminuted displaced radial head fracture

  • dislocation of distal radioulnar joint

Galeazzi Fracture

  • [Ricardo Galeazzi (1866 1952), orthopedic surgeon in Italy]

  • = PIEDMONT FRACTURE

Mechanism: fall on outstretched hand with elbow flexed

Anterior Humeral Line and Elbow fat Pads

  • radial shaft fracture (most commonly) at junction of distal to middle third with dorsal angulation

  • subluxation / dislocation of distal radioulnar joint

  • ulnar plus variance (= radial shortening) of >10 mm implies complete disruption of interosseous membrane = complete instability of radioulnar joint

    Cx: (1) High incidence of nonunion, delayed union, malunion (unstable fracture)
    (2) Limitation of pronation / supination

Monteggia-type Fracture

= fracture of ulnar shaft + dislocation of radial head

Bado Classification:

  • [Jose Luis Bado (1903 1977), orthopedic surgeon from Uruguay]

  • Type I = classic Monteggia fracture

    • [Giovanni Battista Monteggia (1762 1815), Italian surgeon]

      Mechanism: direct blow to the forearm

    • anteriorly angulated proximal ulnar fracture

    • anterior dislocation of radial head

    • may have associated wrist injury

      Cx: nonunion, limitation of motion at elbow, nerve abnormalities

  • Type II = reverse Monteggia fracture

    • radial head displaced posteriorly / posterolaterally

    • dorsally angulated proximal ulnar fracture

  • Type III

    • anterior / anterolateral dislocation of radial head

    • ulnar metaphyseal fracture

  • Type IV

    • anterior displacement of radial head

    • fracture of proximal third of radius + ulna at the same level

Smith Fracture

  • = REVERSE COLLES FRACTURE = REVERSE BARTON FRACTURE = GOYRAND FRACTURE (term used in France)

  • [Robert William Smith (1807 1873), succeeding Colles as professor of surgery at Trinity College in Dublin, Ireland]

Mechanism: hyperflexion with fall on back of hand

  • nonarticular distal radial fracture

  • ventral displacement of fragment

  • radial deviation of hand

  • garden spade deformity

    Cx: altered function of carpus

Elbow Fracture

  • common among children 2 14 years of age

  • @ Soft-tissue

    • displacement of anterior + posterior fat pads

      (= elbow joint effusion with supracondylar / lateral condylar / proximal ulnar fractures)

    • supinator fat pad (= fracture of proximal radius)

    • focal edema medially (= medial epicondyle fx) / laterally (= lateral condyle fx)

  • @ Humerus (80%)

    • Supracondylar fracture (55%)

      Mechanism: hyperextension with vertical stress

      • transverse fracture line

      • distal fragment posteriorly displaced / tilted

        • P.88


      • anterior humeral line intersecting anterior to posterior third of capitellum (on lateral x-ray)

        Fractures of the Acetabulum

    • Lateral condylar fracture (20%)

      Mechanism: hyperextension with varus stress

      • fracture line between lateral condyle + trochlea / through capitellum

    • Medial epicondylar fracture (5%)

      Mechanism: hyperextension with valgus stress

      • avulsion of medial epicondyle (by flexor muscles of forearm)

      • may become trapped in joint space (after reduction of concomitant elbow dislocation)

  • @ Radius (10%)

    Mechanism: hyperextension with valgus stress

    • Salter-Harris type II / IV fracture

    • transverse metaphyseal / radial neck fracture

    Mechanism: hyperextension with varus stress

    • dislocation as part of Monteggia fracture (from rupture of annular ligament)

  • @ Ulna (10%)

    • longitudinal linear fracture through proximal shaft

      Mechanism: hyperextension with vertical stress

    • transverse fracture through olecranon

      Mechanism: hyperextension with valgus / varus stress; blow to posterior elbow in flexed position

    • coronoid process avulsion

      Mechanism: hyperextension-rotation associated with forceful contraction of brachial m.

Rib Fracture

Associated with: pneumothorax, hemothorax, lung contusion / laceration

  • @ 1st rib

    • Indicates substantial trauma (due to protected location)

      Cause: acute trauma / fatigue fracture (from carrying a heavy back pack)
      Associated with: aortic / great vessel injury; thoracic vertebral fracture; scapular fracture

  • @ Lower ribs

    Associated with: injury to upper abdominal organs / diaphragm

Malgaigne Fracture

P.89


Flail Chest

  • = fracture of >4 contiguous ribs

  • paradoxic motion of chest wall with respiration

  • respiratory failure

Cough Fracture

Location: 4 9th rib in anterior axillary line

Pelvic Fracture

Unstable pelvic fractures:

  • anterior compression

    • Bilateral vertical pubic rami fractures

    • Symphysis + sacroiliac joint diastasis

  • lateral compression

    • Malgaigne (ipsilateral anterior + posterior fx)

    • Bucket-handle (contralateral anterior + posterior fx)

  • vertical shear

    • Superior displacement of pelvis

Acetabular Fracture

Anatomy & Function:

  • most important portion of acetabulum is roof / dome;

  • weight-bearing surface for entire lower limb is derived + supported by 2 columns which are oriented in an inverted Y and join above the acetabular roof at an angle of 60 :

    • anterior iliopubic column of acetabulum

    • posterior ilioischial column of acetabulum

Classification (Judet and Letournel):

  • Elementary fractures

    Posterior wall 27% Anterior column 5%
    Transverse 9% Posterior column 4%
    Anterior wall 2%    

  • Associated fractures

    Transverse + posterior wall 27%
    Both columns 19%
    T-shaped 6%
    Anterior wall + posterior hemitransverse 5%
    Posterior column + posterior wall 3%

Duverney Fracture

Posterior wall (lip / rim) fracture (27%)

Mechanism: indirect force transmitted through length of femur with flexed hip joint (knee strikes dashboard)
Associated with: posterior dislocation of femur

Transverse fracture (9%)

N.B.: most difficult to diagnose + comprehend

  • transects both the iliopubic + ilioischial columns with fracture line in an anteroposterior direction

Anterior column fracture (5%)

Mechanism: blow to greater trochanter with hip externally rotated
Associated with: posterior column / transverse fracture

  • fracture begins between anterior iliac spines + traverses the acetabular fossa + ends in the ischiopubic ramus

Posterior column fracture (4%)

Mechanism: indirect force transmitted through length of femur with hip abducted
Associated with: posterior dislocation of femur + sciatic nerve injury

  • fracture begins at greater sciatic notch + traverses the posterior aspect of acetabular fossa + ends in the ischiopubic ramus

Anterior wall fracture (2%)

Mechanism: force transmitted through greater trochanter
Associated with: posterior dislocation of femur + sciatic nerve injury

  • fracture begins on anterior rim of acetabulum + emerges on lateral aspect of superior pubic ramus

Malgaigne Fracture

  • [Joseph Fran ois Malgaigne (1806 1865), French surgical historian, published first comprehensive book on fractures]

  • = fracture-dislocation of one side of the pelvis with anterior + posterior disruption of pelvic ring

P.90


Tibial Plateau Fractures

Mechanism: direct trauma

  • shortening of involved extremity

  • vertical fractures through one side of pelvic ring

    • superior to acetabulum (ilium)

    • inferior to acetabulum (pubic rami)

    • sacroiliac dislocation / fracture

  • lateral unstable fragment contains acetabulum

Bucket Handle Fracture

  • double vertical fracture through superior and inferior pubic rami + sacroiliac joint dislocation on contralateral side

Duverney Fracture

  • [Joseph Guichard Duverney (1648 1730), French surgeon]

  • isolated fracture of iliac wing

Knee Fracture

Segond Fracture

  • [Paul Ferdinand Segond (1851 1912), surgeon in chief at Salp tri re in Paris, France]

    Mechanism: external rotation + varus stress causing excessive tension on the lateral capsular ligament
    Associated with: lesion of anterior cruciate ligament (75 100%), meniscal tear (67%)

  • anterolateral instability of the knee

  • small cortical avulsion fracture of proximal lateral tibial rim just distal to lateral plateau

Tibial Plateau Fracture (Schatzker classification)

Mechanism: valgus force ( bumper / fender fracture from lateral force of automobile against a pedestrian's fixed knee) / compression force often in extension
Type I = wedge-shaped pure cleavage fracture 6%
Type II = combined cleavage + median compression fracture 25%
Type III = pure compression fracture 36%
Type IV = medial plateau fracture with a split /depressed comminution 10%
Type V = bicondylar fracture, often withinverted Y appearance 3%
Type VI = transverse / oblique fracture withseparation of metaphysis fromdiaphysis 20%

  • Lateral plateau fractures (type I III) are most common!

  • Fractures of medial plateau are associated with greater violence and higher percentage of associated injuries!

Foot Fracture

Ankle Fracture

Incidence: ankle injuries account for 10% of all emergency room visits; 85% of all ankle sprains involve lateral ligaments

Ligamentous connections at ankle:

  • binding tibia + fibula

    • anterior inferior tibiofibular ligament (= tibiofibular syndesmosis)

    • posterior inferior tibiofibular ligament

    • transverse tibiofibular ligament

    • interosseous membrane

  • lateral malleolus

    85% of all ankle sprains involve these ligaments:

    • anterior talofibular ligament

    • posterior talofibular ligament

    • calcaneofibular ligament

  • medial malleolus = deltoid ligament with

    • navicular portion

    • sustentaculum portion

    • talar portion

Lateral Malleolar Fractures

Weber Type A

  • [Bernhard Georg Weber (1929 ), orthopedic surgeon in St. Gall, Switzerland]

  • = SUPINATION-ADDUCTION INJURY = INVERSION-ADDUCTION INJURY

  • Mechanism:

    • avulsive forces affect lateral ankle structures

    • impactive forces secondary to talar shift stress medial structures

  • sprain / rupture of lateral collateral ligament

    • Anterior tibiofibular ligament ruptures alone in 66%

    • Injury of all 3 lateral ligaments in 20%

      P.91


      Prognosis: chronic lateral ankle instability in 10 20%

    • transverse avulsion of malleolus sparing tibiofibular ligaments

    • oblique fracture of medial malleolus

    • posterior tibial lip fracture

Weber Type B

  • = SUPINATION-ABDUCTION INJURY = EVERSION-EXTERNAL ROTATION

  • Mechanism:

    • avulsive forces on medial structures

    • impacting forces on lateral structures (talar impact)

  • oblique / spiral fracture of lateral malleolus starting at level of joint space extending proximally

  • lateral subluxation of talus

  • partial disruption of tibiofibular ligament

  • sprain / rupture / avulsion of deltoid ligament

  • transverse fracture of medial malleolus

  • Dupuytren Fracture

    • [Guillaume Dupuytren (1777 1835), French surgeon]

    • fracture of distal fibula above a disrupted tibiofibular ligament + disruption of deltoid ligament

  • LeFort Fracture of Ankle

    • [Leon Clement LeFort (1829 1893), French surgeon]

    • vertical fracture of anterior medial portion of distal fibula

    • avulsion of anterior tibiofibular ligament

Ankle Fractures

Maisonneuve Fracture

Weber Type C

  • = PRONATION-EXTERNAL ROTATION = EVERSION + EXTERNAL ROTATION

  • fibular fracture higher than ankle joint (Maisonneuve fracture if around knee)

  • deltoid ligament tear

  • medial malleolar fracture

  • tear of tibiofibular ligament / avulsion of anterior tubercle (Tillaux-Chaput) / avulsion of posterior tubercle (Volkmann)

  • tear of interosseous membrane = lateral instability

  • Tillaux Fracture

    • [Paul Jules Tillaux (1834 1904), French surgeon and anatomist]

    • avulsion injury of anterior tibial tubercle at attachment of distal anterior tibiofibular ligament

  • Maisonneuve Fracture

    • [Jacques Gilles Maisonneuve (1809 1897), student of Dupuytren]

    • tear of distal tibiofibular syndesmosis + interosseous membrane

    • spiral fracture of upper third of fibula

    • associated fracture of medial malleolus / rupture of deep deltoid ligament

Chopart Fracture

  • [Fran ois Chopart (1743 1795), surgeon in Paris, France]

  • fracture-dislocation through midtarsal / Chopart (calcaneocuboid + talonavicular) joint

  • commonly associated with fractures of the bones abutting the joint

Jones Fracture

  • [Robert Jones (1857 1933), British orthopedic surgeon and pioneer in radiology described fracture in Ann Surg 1902]

    Mechanism: adduction of forefoot with ankle in plantar flexion

  • transverse fracture at base of 5th metatarsal bone at junction of diaphysis and metaphysis (>1.5 cm distal to proximal tip of metatarsal tuberosity)

    Cx: delayed union / nonunion (poor blood supply)

P.92


Peroneus Brevis Avulsion Fracture

  • = METATARSAL 5 TUBEROSITY FRACTURE

  • Most common fracture of the proximal 5th metatarsal bone

    Mechanism: plantar flexion + inversion (stepping off a curb)

  • transverse avulsion fracture of base of 5th metatarsal bone

    Location: proximal to metatarsal tuberosity (insertion of peroneus brevis tendon); usually extraarticular
    DDx: Jones fracture (slightly different location)

Lisfranc Fracture

  • [Jacques Lisfranc De Saint Martin (1790 1847), surgeon in Napoleon's army]

    Mechanism: metatarsal heads fixed and hindfoot forced plantarward and into rotation

  • fracture-dislocation / fracture-subluxation of tarsometatarsal joints (typically 2 through 5)

  • lateral displacement of metatarsals

Shepherd Fracture

  • [Francis J. Shepherd (1851 1929), demonstrator in anatomy at McGill University in Montreal, Canada]

  • fracture of lateral tubercle of posterior process of talus

    DDx: os trigonum

Calcaneal Fracture

Incidence: most commonly fractured tarsal bone; 60% of all tarsal fractures; 2% of all fractures in the body; commonly bilateral
Mechanism: fall from heights
May be associated with: lumbar vertebral fracture
Age: 95% in adults, 5% in children
adulthood: intraarticular (75%), extraarticular (25%)
childhood: extraarticular (63 92%)

No Caption Available.

Classification:

  • extraarticular fracture of calcaneal tuberosity:beak type, vertical, horizontal, medial avulsion

  • intraarticular fracture

    • subtalar joint involvement: undisplaced, displaced, comminuted

    • calcaneocuboid joint involvement

  • apex of lateral talar process does not point to crucial angle of Gissane

  • Boehler angle decreased below 28 40

Frostbite

Cause: (1) cellular injury + necrosis from freezing process
(2) cessation of circulation secondary to cellular aggregates + thrombi forming as a result of exposure to low temperatures below 13 C (usually cold air)

  • firm white numb areas in cutis (separation of epidermal-dermal interface)

Location: feet, hands (thumb commonly spared due to protection by clenched fist)

Early changes:

  • soft-tissue swelling + loss of tissue at tips of digits

CHILD

  • fragmentation / premature fusion / destruction of distal phalangeal epiphyses

  • secondary infection, articular cartilage injury, joint space narrowing, sclerosis, osteophytosis of DIP

  • shortening + deviation / deformity of fingers

ADULT

  • osteoporosis (4 10 weeks after injury)

  • periostitis

  • acromutilation (secondary to osteomyelitis + surgical removal) + tuftal resorption (result of soft-tissue loss)

  • small round punched-out areas near edge of joint

  • interphalangeal joint abnormalities (simulating osteoarthritis)

  • calcification / ossification of pinna

Angio:

  • vasospasm, stenosis, occlusion

  • proliferation of arterial + venous collaterals (in recovery phase)

Bone scintigraphy:

  • persistent absence of uptake (= lack of vascular perfusion) indicates nonviable tissue

Rx: selective angiography with intraarterial reserpine

Ganglion

Ganglion cyst = mucin-containing cyst arising from tendon sheath / joint capsule / bursa / subchondral bone lined by flat spindle-shaped cells
Synovial cyst = cyst continuous with joint capsule lined by synovial cells (term is used by some synonymously with ganglion)

Soft-tissue Ganglion

= cystic tumorlike lesion usually attached to a tendon sheath

P.93


Origin: synovial herniation / coalescence of smaller cysts formed by myxomatous degeneration of periarticular connective tissue

  • asymptomatic / pain

  • uni- / multilocular swelling

    Location: hand, wrist, foot (over dorsum)
    Site: arise from tendon, muscle, semilunar cartilage

  • soft-tissue mass with surface bone resorption

  • periosteal new-bone formation

  • arthrography may demonstrate communication with joint / tendon sheath

  • internal septations, lobulated configuration

  • hypointense relative to muscle on T1WI / hyperintense content (protein, hemorrhage)

  • hyperintense relative to fat on T2WI

  • no enhancement

Prognosis: may resolve spontaneously
Rx: steroid injection may improve symptomatology
DDx on MRI: myxoid lipoma, highly necrotic tumor

Intraosseous Ganglion

  • = benign subchondral radiolucent lesion WITHOUT degenerative arthritis

  • mild localized pain (4% of patients with unexplained wrist pain)

    Age: middle age
    Origin: (1) mucoid degeneration of intraosseous connective tissue perhaps due to trauma / ischemia
    (2) penetration of juxtaosseous soft-tissue ganglion (= synovial herniation) into underlying bone (occasionally)
    Path: uni- / multilocular cyst surrounded by fibrous lining, containing gelatinous material
    Location: epiphysis of long bone (medial malleolus, femoral head, proximal tibia, carpal bones) / subarticular flat bone (acetabulum)

  • well-demarcated solitary 0.6 6 cm lytic lesion

  • sclerotic margin

  • NO communication with joint

  • increased radiotracer uptake on bone scintigraphy (in 10%)

    DDx: posttraumatic / degenerative cyst

Periosteal Ganglion

  • = cystic structure with viscid / mucinous contents

    Incidence: 11 cases in literature
    Age: 39 50 years; M > F

  • swelling, mild tenderness

    Location: long tubular bones of lower extremity

  • cortical erosion / scalloping / reactive bone formation

  • NO intraosseous component (endosteal surface intact)

  • CT:

    • well-defined soft-tissue mass adjacent to bone cortex with fluid contents

    MR:

    • homogeneous isointense signal to muscle on T1WI

    • homogeneous hyperintense signal to fat on T2WI

    • NO internal septations (DDx to soft-tissue ganglion)

    DDx: periosteal chondroma without matrix calcification, cortical desmoid, subperiosteal aneurysmal bone cyst, acute subperiosteal hematoma (history of trauma / blood dyscrasia), subperiosteal abscess (involvement of adjacent bone marrow)
    Rx: surgical excision (local recurrence possible)

Gardner Syndrome

  • = autosomal dominant syndrome characterized by

    • osteomas

    • soft-tissue tumors

    • colonic polyps

    Location of osteomas: paranasal sinuses; outer table of skull (frequent); mandible (at angle)

  • endosteal cortical thickening / osteomas in any bone

  • may have solid periosteal cortical thickening

  • osteomas / exostoses may protrude from periosteal surface

  • wavy cortical thickening of superior aspect of ribs

  • polyps: colon, stomach, duodenum, ampulla of Vater, small intestine

    Cx: high incidence of carcinoma of duodenum / ampulla of Vater

Gaucher Disease

  • = rare autosomal recessive / dominant (in a few) lipid storage disorder; the most common lysosomal storage disorder;

  • M = F

    Incidence: 1:50,000 100,000 (general population); 1:500 1,000 (in Ashkenazi Jews)
    Etiology: deficiency of lysosomal hydrolase acid -glycosidase (= beta-glucocerebrosidase) leads to accumulation of glucosylceramide (glucocerebroside) within macrophages of RES (liver, spleen, bone marrow, lung, lymph nodes)
    Histo: bone-marrow aspirate shows Gaucher cells (kerasin-laden histiocytes) of 20 100 m in diameter with a foamy wrinkled-paper appearance

  • Clinical types:

    • Adult / chronic nonneuropathic form

      • = type 1 (most common form in USA)

        Age of onset: 3rd 4th decade

      • no clinical signs (most)

        Prognosis: longest time of survival; pulmonary involvement / hepatic failure may lead to early death

    • Rapidly fatal infantile / acute neuropathic form

      • = type 2

        Age of onset: 1 3 12 months

      • early onset of significant hepatosplenomegaly

      • severe progressive neurologic symptoms: seizures, mental retardation, strabismus, spasticity

      • skeletal manifestations are rare

        Prognosis: fatal during first 2 years of life

    • Juvenile / subacute neuropathic form

      • = type 3 (rarest type)

        Age of onset: 2 6 years

      • variable hepatosplenomegaly

      • mild neurologic involvement: seizures

      • delayed onset of skeletal manifestations

        Prognosis: survival into adolescence

  • hepatosplenomegaly, impairment of liver function, ascites

  • elevated serum acid phosphatase

    • P.94


  • pancytopenia, anemia (chronic fatigue), leukopenia, thrombocytopenia (easy bruising, hypersplenism)

  • hemochromatosis (yellowish brown pigmentation of conjunctiva + skin)

  • dull bone pain (bone involvement in 75%)

    Location: predominantly long tubular bones (distal femur), axial skeleton, hip, shoulder, pelvis; bilateral

  • generalized osteopenia (decrease in trabecular bone density):

    • striking cortical thinning + bone widening

    • endosteal scalloping (due to marrow packing)

  • numerous sharply circumscribed lytic lesions resembling metastases / multiple myeloma (marrow replacement)

  • periosteal reaction = cloaking

  • Erlenmeyer flask deformity of distal femur + proximal tibia (2 to marrow infiltration) MOST CHARACTERISTIC

  • weakening of subchondral bone:

    • osteonecrosis (common, frequently of femoral head)

    • degenerative arthritis

  • bone infarcts in long-bone metaphyses (most common in femoral + humeral heads):

    • focal / serpentine areas of sclerosis

    • bone-within-bone appearance

  • H-shaped / step-off / biconcave fish-mouth vertebrae (DDx: sickle cell disease)

  • MR:

    • focal / diffuse replacement of adipocytes in bone marrow by Gaucher cells results in decreased marrow signal on T1WI + T2WI (marrow involvement follows the distribution of hematopoietic marrow in spine, pelvis, proximal femoral metaphysis; from proximal to distal in appendicular skeleton):

      • epiphyses generally not involved

      myelofibrotic marrow of low signal intensity on T1WI + T2WI (in long-standing disease)

  • @ Liver

    • hepatomegaly

    • nonspecific fatty + cirrhotic changes

    • focal lesions hypointense on T1WI + hyperintense to isointense on T2WI

  • @ Spleen

    • splenomegaly + lymphadenopathy

    • multiple nodular lesions (= clusters of RES cells laden with glucosylceramide):

      • hypodense without enhancement on CT

      • hypoechoic / hyperechoic on US

      • slightly hypointense to isointense on T1WI

      • hypointense (Gaucher cells / fibrosis) or hyperintense (dilated sinusoids filled with blood around Gaucher cell infiltrates) on T2WI

    • splenic infarcts leading to fibrosis, especially in massively enlarged spleen

  • @ Lung

    • normal

    • nonspecific diffuse reticulonodular / miliary infiltrates at lung bases (= infiltration with Gaucher cells)

Dx: elevated serum activity of -glucocerebrosidase; genotyping
Cx: >90% have orthopedic complications at some time
(1) Pathologic fractures + compression fractures of vertebrae
(2) Avascular necrosis of femoral head, humeral head, wrist, ankle (common)
(3) Osteomyelitis (increased incidence)
(4) Myelosclerosis in long-standing disease
(5) Repeated pulmonary infections
(6) Cancer of hematopoietic origin (14.7-fold risk)
Prognosis: highly variable clinical course; strong relationship between splenic volume and disease severity
Rx: no cure; bone marrow transplantation; enzyme replacement therapy with Cerezyme
DDx: metastatic disease, multiple myeloma, leukemia, sickle-cell disease, fibrous dysplasia

Giant Cell Reparative Granuloma

= GIANT CELL REACTION = GIANT CELL GRANULOMA

Cause: ? reactive inflammatory process to trauma / infection (not a true neoplasm)
Histo: numerous giant cells in exuberant fibrous matrix arranged in clusters around foci of hemorrhage + commonly exhibiting osteoid formation (unusual in giant cell tumor); indistinguishable from brown tumor of HPT; cystic degeneration + ABC components distinctly uncommon
Peak age: 2nd + 3rd decade (ranging from childhood to 76 years); 74% <30 years of age; M:F = 1:1
May be associated with: enchondromatosis, Goltz syndrome, fibrous dysplasia, Paget disease

Location:

  • @ Gnathic (1 7% of all benign oral tumors):

    • gingiva + alveolar mucosa of mandible, maxilla

      • central type = in bone

      • peripheral type = in gingival soft tissue

    • M:F = 1:2

    • nonspecific pain + swelling (increasing during pregnancy)

    • expansile remodeling of bone with multilocular appearance

    • thinned usually intact cortex

      DDx: indistinguishable from odontogenic cyst, ABC, ameloblastoma, odontogenic myxoma, odontogenic fibroma

  • @ Small bones of hand + feet (less common): phalanges of hand > metcarpals > metatarsals > carpal bones > tarsal bones > phalanges of foot

    • M:F = 1:1

    • nonspecific pain + swelling for months to years

      Site: metaphysis extension into diaphysis; extension into epiphysis is UNCOMMON

    • expansile lytic defect of 2 2.5 cm in diameter with internal trabeculations

    • thinning of overlying cortex

    • matrix mineralization may be seen (DDx to GCT)

    • periosteal reaction is unusual (as in GCT)

    • extension beyond cortex is unusual

  • @ Other locations (rare):

    • ethmoid sinus, sphenoid sinus, temporal bone, skull, spine, clavicle, tibia, humerus, ribs, femur

Cx: pathologic fracture
Prognosis: may recur; no malignant transformation
Rx: curettage (22 50% recurrence rate) / local excision
DDx: (1) Enchondroma (same location, matrix calcification)
(2) Aneurysmal bone cyst (rare in small bones of hand + feet, typically prior to epiphyseal closure)
(3) Giant cell tumor (more aggressive appearance)
(4) Infection (clinical)
(5) Brown tumor of HPT (periosteal bone resorption, abnormal Ca + P levels)

P.95


Giant Cell Tumor

  • = OSTEOCLASTOMA = OSTEOBLASTOCLASTOMA = TUMOR OF MYELOPLEXUS = MYELOID SARCOMA

  • = nonmineralized lytic eccentric metaepiphyseal lesion involving a long bone with extension to subarticular bone in the skeletally mature patient

Origin: probably arise from zone of intense osteoclastic activity (of endochondral ossification) in skeletally immature patients
Incidence: 4 9.5% of all primary bone tumors; 18 23% of benign skeletal tumors; unusually high prevalence in China + southern India
Path: friable vascular stroma of numerous thin-walled capillaries with necrosis + hemorrhage + cyst formation (DDx: aneurysmal bone cyst without solid areas)
Histo: large number of multinucleated osteoclastic giant cells in a diffuse distribution in a background of mononuclear cells intermixed throughout a spindle cell stroma (DDx: giant cells characteristic of all reactive bone disease as in pigmented villonodular synovitis, benign chondroblastoma, nonosteogenic fibroma, chondromyxoid fibroma, fibrous dysplasia)
Age: peaks in 3rd decade; 1 3% < age 14; 80% between 20 and 50 years; 9 13% > age 50; M:F = 1:1.1 to 1:1.5 (in spine 1:2.5)
May be associated with: Paget disease (in 50 60% located in skull + facial bones)

Staging:

Stage 1 indolent radiographic + histologic appearance (10 15%)
Stage 2 more aggressive radiographic appearance with expansile remodeling (70 80%)
Stage 3 extension into adjacent soft tissues with histologically benign appearance (10 15%)

  • pain at affected site (most common in 10% pathologic fracture)

  • local swelling + tenderness

  • weakness + sensory deficits (if in spine)

Location:

  • @ long bones (75 85 90%)

    • lower extremity (50 65% about knee):

      • distal end of femur (23 30%) > proximal end of tibia (20 25%) > proximal femur (4%) > distal tibia (2 5%) > proximal fibula (3 4%) > foot (1 2%)

        • RARE in patella (the largest sesamoid bone) + greater trochanter (epiphyseal equivalent)

    • upper extremity (away from elbow):

      • distal end of radius (10 12%) > proximal end of humerus (4 8%) > hand and wrist (1 5%)

  • @ flat bones (15%)

    • pelvis: sacrum near SIJ (4%), iliac bone (3%)

    • spine (3 6%): thoracic > cervical > lumbar spine (tumor frequency 2nd only to chordoma)

    • rib (anterior / posterior end)

    • skull (sphenoid bone)

      Site: eccentric (42 93%) in metaphysis of long bones adjacent to ossified epiphyseal line; extension to within 1 cm of subarticular bone (84 99%) after fusion of epiphyseal plate (MOST TYPICAL) with possible transarticular spread

    • The open epiphyseal plate acts as a barrier to tumor growth!

  • well-circumscribed expansile solitary lytic bone lesion with a narrow zone of transition:

    • wide zone of transition (10 20%)

    • large lesions are more centrally located

  • soap bubble appearance (47 60%) = expansile remodeling with multiloculated appearance:

    • NO internal mineralization of tumor matrix

    • prominent trabeculation (33 57%):

      • reactive with appositional bone growth

      • pseudotrabeculation of osseous ridges in endosteal scalloping

  • no sclerosis (80 85%) / periosteal reaction (10 30%) due to aggressive rapid growth in absence of fracture

  • cortical penetration (33 50%):

    • cortical thinning

    • soft-tissue invasion (25%)

    • complete / incomplete pathologic fracture (11 37%)

  • destruction of vertebral body with secondary invasion of posterior elements (DDx: ABC, osteoblastoma)

  • frequently vertebral collapse

  • involves adjacent vertebral disks + vertebrae, crosses sacroiliac joint

  • may cross joint space in long bones (exceedingly rare)

  • NUC:

    • diffusely increased uptake doughnut sign (57%) of central photopenia on delayed bone scintigraphy

    • increased uptake across an articulation + in adjacent joints (62%) due to increased blood flow + disuse osteoporosis and NOT tumor extension

  • Angio:

    • hypervascular (60 65%) / hypovascular (20%) / avascular (10%) lesion

  • CT:

    • tumor of soft-tissue attenuation similar to muscle with foci of low attenuation (hemorrhage / necrosis):

      • NO matrix mineralization

      well-defined margins thin rim of sclerosis (in up to 20%)

    • soft-tissue extension (33 44%) usually at metaphyseal end of tumor

    • aneurysmal bone cyst components (in 14%) of low density with fluid levels

    • joint involvement is unusual except for sacroiliac joint (38%) with sacral lesion

    • significant enhancement

  • MR:

    • relatively well-defined lesion of heterogeneous signal intensity with low to intermediate intensity on T1WI + T2WI (63 96%) due to increased cellularity + high collagen content + hemosiderin

      P.96


      • HELPFUL feature to distinguish from other subarticular lesions (solitary subchondral cyst, intraosseous ganglion, Brodie abscess, clear cell chondrosarcoma with hyperintense matrix on T2WI)

      focal aneurysmal bone cyst components (in 14%) in tumor center with marked hyperintensity on T2WI

      • Direct biopsy to peripheral solid-tissue component to prevent misdiagnosis!

      low-signal-intensity margin (= osseous sclerosis / pseudocapsule

    • significant enhancement of solid-tissue component

Cx: in 5 10% malignant transformation within first 5 years (M:F = 3:1); metastases to lung
Prognosis: locally aggressive; 80 90% recurrence rate within first 3 years after initial treatment
Rx: currettage + bone grafting (40 60% recurrence); currettage with filling of void with high-speed burr + polymethylmethacrylate (2 25% recurrence); wide resection (7% recurrence) and reconstruction with allografts / metal prosthesis; radiation therapy for inoperable GCT (39 63% recurrence)
DDx: (1) Aneurysmal bone cyst (contains only cystic regions; in posterior elements of spine)
(2) Brown tumor of HPT (lab values)
(3) Osteoblastoma
(4) Cartilage tumor: chondroblastoma, enchondroma (not epiphyseal), chondromyxoid fibroma, chondrosarcoma
(5) Nonossifying fibroma
(6) Bone abscess
(7) Hemangioma
(8) Fibrous dysplasia
(9) Giant cell reparative granuloma

Multifocal Giant Cell Tumor

= additional GCTs (up to a maximum of 20) developing synchronously / metachronously for up to 20 years without increased risk of pulmonary metastases

Incidence: <1% of all GCT cases
Age: 25 years (range, 11 62 years); M<F
May be associated with: Paget disease, usually polyostotic (GCT develops at a mean age of 61 years + after an average time lapse of 12 years) with involvement of skull + facial bones
Location: increased prevalence of hands + feet

Malignant Giant Cell Tumor

= group of giant cell containing lesions capable of malignant behavior + pulmonary metastases

Prevalence: 5 10% of all GCTs
Age: older than patients with benign GCTs

Types:

  • Benign metastasizing GCT

    Prevalence: 1 5%

    • pulmonary metastases may remain stable / regress spontaneously

    • pulmonary nodules may show peripheral ossification

    Prognosis: death in 13%

  • Primary malignant transformation of GCT

    • = malignant tumor of bone composed of a sarcomatous growth juxtaposed to zones of typical benign GCT without a history of radiation therapy / repeated currettage / resection

      Prognosis: median survival time of 4 years

  • Secondary malignant GCT (86%)

    • = sarcomatous growth that occurs at a site of previously documented GCT usually after radiation therapy (80%) / repeated resections

      Prognosis: median survival time of 1 year

  • Osteoclastic (giant cell) sarcoma

    • = highly malignant tumor composed of anaplastic osteoclast-like giant cells without tumor osteoid / bone / cartilage

Glomus Tumor

  • = hamartoma composed of cells derived from neuro-myoarterial apparatus (regulating blood flow in skin)

  • Glomus body = encapsulated oval organ of 300 m length; located in reticular dermis (= deepest layer of skin); concentrated in tips of digits (93 501/cm2); composed of an afferent arteriole, an anastomotic vessel (= Sucquet-Hoyer canal lined by endothelium + surrounded by smooth muscle fibers), a primary collecting vein, the intraglomerular reticulum + capsule

    Histo: (a) vascular (b) myxoid (c) solid form
    Prevalence: 1 5% of soft-tissue tumors of hand
    Age: mostly in 4 5th decade

  • joint tenderness + pain (on average of 4 7 years duration prior to diagnosis)

  • Love test = eliciting pain by applying precise pressure with a pencil tip

  • Hildreth sign = disappearance of pain after application of a tourniquet proximally on arm (PATHOGNOMONIC)

  • @ SUBUNGUAL GLOMUS TUMOR

    • increased distance between dorsum of phalanx + underside of nail (25%)

    • extrinsic bone erosion (14 25 65%), often with sclerotic border

    • small hypoechoic tumor by US (>3 mm detectable)

    • homogeneously high-signal intensity lesion on T2WI (detectable if >2 mm in diameter)

  • @ GLOMUS TUMOR OF BONE occasionally within bone

    • resembles enchondroma

    DDx: (1) Mucoid cyst (painless, in proximal nail fold, communicating with DIP joint, associated with osteoarthritis)
    (2) Angioma (more superficially located)

Gout

= characterized by derangement of purine metabolism manifested by:

  • hyperuricemia

  • deposition of positively birefringent monosodium urate monohydrate crystals in synovial fluid leukocytes

  • gross deposits of sodium urate in periarticular soft tissues (synovial membranes, articular cartilage, ligaments, bursae)

  • recurrent episodes of arthritis

P.97


Age: >40 years; males (in women gout may occur after menopause)

Cause:

  • Primary Gout (90%)

    Incidence: 0.3%; M:F = 20:1; 5% in postmenopausal women

    Disturbance:

    • overproduction of uric acid due to inborn error of metabolism

    • inherited defect in renal urate excretion

    • Idiopathic (99%)

      • normal urinary excretion (80 90%)

      • increased urinary excretion (10 20%)

    • Specific enzyme / metabolic defect (1%)

      • increased activity of PP-ribose-P synthetase

      • partial deficiency of hypoxanthine-guanine phosphoribosyltransferase

  • Secondary Gout (10%)

    • Rarely cause for radiographically apparent disease

    • increased turnover of nucleic acids:

      • Myeloproliferative disorders + sequelae of their treatment: polycythemia vera, leukemia, lymphoma, multiple myeloma

      • Blood dyscrasias: chronic hemolysis

    • increase in purine synthesis de novo due to enzyme defects:

      • Glycogen storage disease Type I (von Gierke = glucose-6-phosphatase deficiency)

      • Lesch-Nyhan syndrome (choreoathetosis, spasticity, mental retardation, self-mutilation of lips + fingertips) due to absence of hypo-xanthine-guanine phosphoribosyltransferase

    • acquired defect in renal excretion of urates (due to reduction in renal function):

      • Chronic renal failure

      • Drugs, toxins: lead poisoning

      • Endocrinologic: myxedema, hypo- / hyperparathyroidism

      • Vascular: myocardial infarction, hypertension

Histo: tophus (PATHOGNOMONIC LESION) composed of crystalline / amorphous urates surrounded by highly vascularized inflammatory tissue rich in histiocytes, lymphocytes, fibroblasts, foreign-body giant cells (similar to a foreign-body granuloma)

Clinical stages in chronologic order:

  • Asymptomatic hyperuricemia

  • Acute gouty arthritis

    • Gout accounts for 5% of all cases of arthritis

      Precipitated by: trauma, surgery, alcohol, dietary indiscretion, systemic infection

    • monoarticular (90%)

    • polyarticular (10%): any joint may be affected

      Prognosis: usually self-limited (pain resolving within a few hours / days) without treatment

  • Chronic tophaceous gout

    • = multiple large urate deposits in intraarticular, extraarticular, intraosseous location

      Prevalence: <50% of patients experiencing acute attacks; M:F = 20:1
      Histo: cartilage degeneration + destruction, synovial proliferation + pannus, destruction of sub-articular bone + proliferation of marginal bone
      Distribution: symmetric polyarticular disease (resembling rheumatoid arthritis), asymmetric polyarticular disease, monoarticular disease

    • more severe prolonged attacks

    • may ulcerate expressing whitish chalky material

      Cx: tendon rupture, nerve compression / paralysis

  • Gouty nephropathy / nephrolithiasis

    • Acute urate nephropathy

    • Uric acid urolithiasis

      • May precede arthritis in up to 20% of cases!

      • renal hypertension

      • isosthenuria (inability to concentrate urine)

      • proteinuria

      • pyelonephritis

        Cx: increased incidence of calcium oxalate stones (urate crystals serve as a nidus)

Location:

  • joints: hands + feet (1st MTP joint most commonly affected = podagra) > ankles > heels > wrists (carpometacarpal compartment especially common and severe) > fingers > elbows; knees; shoulder; sacroiliac joint (15%, unilateral);

    • involvement of hip + spine is rare

  • bones, tendon, bursa, bones

  • external ear; pressure points over elbow, forearms, knees, feet

  • Radiologic features usually not seen until 6 12 years after initial attack

  • Radiologic features present in 45% of inflicted patients

  • @ Soft tissues

    • eccentric juxtaarticular lobulated soft-tissue masses (hand, foot, ankle, elbow, knee)

      Site: tendency for extensor tendons, eg, quadriceps, triceps, Achilles tendon

    • calcific deposits in periphery of gouty tophi in 50% (sodium urate crystals are not radiopaque, tophi radiographically visible only after calcium deposition of an underlying abnormality of calcium metabolism)

    • bilateral effusion of bursae olecrani (PATHOGNOMONIC), prepatellar bursa

    • aural calcification

  • @ Joints

    • joint effusion (earliest sign)

    • periarticular swelling (in acute monoarticular gout)

    • preservation of joint space until late in disease (IMPORTANT CLUE):

      • cartilage destruction (late in course of disease)

    • absence of periarticular demineralization (due to short duration of attacks; important DDx for rheumatoid arthritis)

    • eccentric erosions with thin sclerotic margins:

      • scalloped erosion of bases of ulnar metacarpals

    • chondrocalcinosis (5%):

      Location: menisci (fibrocartilage only)

      • Patients with gout have a predisposition for calcium pyrophosphate dihydrate deposition disease (CPPD)

        P.98


        Cx: secondary osteoarthritis

    • round / oval well-marginated subarticular cysts (pseudotumor) up to 3 cm (containing tophus / urate crystal-rich fluid)

      DDx: rheumatoid arthritis (marginal erosions without sclerotic rim, periarticular demineralization)

  • @ Bone

    • punched-out lytic bone lesion sclerosis of margin = mouse / rat bite from erosion of long-standing soft-tissue tophus

    • overhanging margin (40%) = elevated osseous spicule separating tophaceous nodule from adjacent erosion (in intra- and extraarticular locations) (HALLMARK)

    • proliferative bone changes:

      • club-shaped metatarsals, metacarpals, phalanges

      • enlargement of ulnar styloid process

      • diaphyseal thickening

    • ischemic necrosis of femoral / humeral heads

    • intraosseous calcification:

      • punctate / circular calcifications of subchondral / subligamentous regions (DDx: enchondroma)

      • bone infarction due to deposits at vascular basement membrane (DDx: bone island)

  • @ Kidney

    • renal stones (in up to 20%):

      • pure uric acid stones (84%): radiolucent on radiographs, hyperdense on CT

      • uric acid + calcium oxalate (4%)

      • pure calcium oxalate / calcium phosphate (12%)

  • MR:

    • tophus (most frequently) isointense to muscle on T1WI

    • low or intermediate signal intensity on T2WI

    • homogeneous intense enhancement

Rx: colchicine, allopurinol (effective treatment usually does not improve roentgenograms)

DDx:

  • CPPD (pseudogout symptomatology, polyarticular chondrocalcinosis involving hyaline and fibrocartilage + degenerative arthropathy with joint space narrowing)

  • Psoriasis (progressive joint space destruction, paravertebral ossification, sacroiliac joint involvement)

  • Rheumatoid arthritis (nonproliferative marginal bone erosions, fusiform soft-tissue swelling, symmetric distribution, early joint-space narrowing, osteopenia)

  • Joint infection (rapid destruction of joint space, loss of articular cortex over a continuous segment)

  • Amyloidosis (bilateral symmetric involvement, periarticular osteopenia)

  • Xanthomatosis (laboratory work-up)

  • Osteoarthritis (symmetric distribution, elderly women)

Granulocytic Sarcoma

  • = CHLOROMA = MYELOBLASTOMA

  • = extramedullary solid tumor consisting of primitive precursors of the granulocytic series of WBCs (myeloblasts, promyelocytes, myelocytes)

  • Clinical setting:

    • patient with acute myelogenous leukemia (in 3 8%)

    • harbinger of AML in nonleukemic patient (usually developing within 1 year)

    • indicator of impending blast crisis in CML (in 1%) / leukemic transformation in myelodysplastic syndromes (polycythemia rubra vera, myelofibrosis with myeloid metaplasia, hypereosinophilic syndrome)

    • isolated event

  • 60% are of green color (chloroma) due to high levels of myeloperoxidase (30% are white / gray / brown depending on preponderance of cell type + oxidative state of myeloperoxidase)

    Location: orbit, soft tissue, skin, paranasal sinus, lymph node, periosteum, organs, bowel; often multiple
    Site: propensity for bone marrow (arises from bone marrow traversing haversian canal + reaching the periosteum), perineural + epidural tissue

  • osteolysis with ill-defined margins

  • homogeneous enhancement on CT / MR (DDx to hematoma / abscess)

  • MR:

    • isointense to brain / bone marrow / muscle on T1WI + T2WI

      Prognosis: resolution under chemotherapy radiation therapy; recurrence rate of 23%
      DDx: osteomyelitis, histiocytosis X, neuroblastoma, lymphoma, multiple myeloma

Gunshot Injury

Firearms: handgun, rifle (great energy), shotgun

Projectiles:

  • bullet:

    • jacketed bullet with mantle of copper

    • semijacketed bullet = exposed lead at tip

    • nonjacketed bullet

  • pellets of steel / lead:

    • birdshot = small pellets

    • buckshot =large pellets

Assessment:

  • Type of projectile

    • fully jacketed bullets show no trail of lead fragments

    • semi- / nonjacketed bullets distribute lead fragments along bullet track

    • hollow-point bullets transform into mushroom shape

    • lead snowstorm of high-velocity soft-point rifle bullets:

      • conical distribution with apex pointing toward entry site

    • steel pellets remain round, lead pellets become deformed + fragmented

      No Caption Available.

    • P.99


  • Path of projectile

    • bullet tips points to entry wound (after tumbling through 180 ):

      • impact deformation of bullet modifies tumbling

    • bullet + bone fragments deposited along track

    • bone fracture beveled toward the direction of travel

  • Extent of injury

Cx: pellet embolization, magnetization in MRI

Hemangioendothelial sarcoma

  • = HEMANGIOENDOTHELIOMA = HEMANGIOEPITHELIOMA

  • = neoplasm of vascular endothelial cells of intermediate aggressiveness with either benign or malignant behavior

    Histo: irregular anastomosing vascular channels lined by one / several layers of atypical anaplastic endothelial cells
    Age: 4th 5th decade; M:F = 2:1

  • history of trauma / irradiation

Soft-tissue Hemangioendothelioma (common)

Location: deep tissues of extremities
Site: in 50% closely related to a vessel (often a vein)

Osseous Hemangioendothelioma (rare)

Age: 2nd 3rd decade of life; M > F
Location: calvarium, spine, femur, tibia, humerus, pelvis; multicentric lesions in 30% often with regional distribution (less aggressive)

  • eccentric lesion in metaphysis of long bones

  • osteolytic aggressively destructive area with indistinct margins (high grade)

  • well-demarcated margins with scattered bony trabeculae (low grade)

  • osteoblastic area in vertebrae, contiguous through several vertebrae

Metastases to: lung (early)
Prognosis: 26% 5-year survival rate
DDx: aneurysmal bone cyst, poorly differentiated fibrosarcoma, highly vascular metastasis, alveolar rhabdomyosarcoma

Hemangioma

  • Most common benign soft-tissue tumor of vascular origin!

Histo: frequently containing variable amounts of nonvascular elements: fat, smooth muscle, fibrous tissue, bone, hemosiderin, thrombus
Fat overgrowth may be so extensive that some lesion may be misdiagnosed as a lipoma!

  • CAPILLARY HEMANGIOMA (most common)

    • = small-caliber vessels lined by flattened epithelium

    Site: skin, subcutaneous tissue; vertebral body
    Age: first few years of life

    • Juvenile capillary hemangioma = strawberry nevus

      Prevalence: 1:200 births; in 20% multiple
      Prognosis: involutes in 75 90% by age 7 years

    • Verrucous capillary hemangioma

    • Senile capillary hemangioma

    • enlarged arteries + arteriovenous shunting

    • pooling of contrast material

  • CAVERNOUS HEMANGIOMA

    • = dilated blood-filled spaces lined by flattened endothelium

      Site: deeper soft tissues, frequently intramuscular; calvarium
      Age: childhood

    • phleboliths = dystrophic calcification in organizing thrombus (in nearly 50%)

    • large cystic spaces

    • enlarged arteries + arteriovenous shunting

    • pooling of contrast material

      Prognosis: NO involution

  • ARTERIOVENOUS HEMANGIOMA

    = persistence of fetal capillary bed with abnormal communications of an increased number of normal / abnormal arteries and veins

    Etiology: (?) congenital arteriovenous malformation
    Age: young patients
    Site: soft tissues

    • superficial lesion without arteriovenous shunting

    • deep lesion with arteriovenous shunting

      • limb enlargement, bruit

      • distended veins, overlying skin warmth

      • Branham sign = reflex bradycardia after compression

    • large tortuous serpentine feeding vessels

    • fast blood flow + dense staining

    • early draining veins

  • VENOUS HEMANGIOMA

    • = thick-walled vessels containing muscle

      Site: deep soft tissues of retroperitoneum, mesentery, muscles of lower extremities
      Age: adulthood

    • phleboliths

    • serpentine vessels with slow blood flow

    • vessels oriented along long axis of extremity (in 78%) + neurovascular bundle (in 64%)

    • multifocal involvement (in 37%)

    • muscle atrophy with increased subcutaneous fat

    • may be normal on arterial angiography

Osseous Hemangioma

Incidence: 10%
Histo: mostly cavernous; capillary type is rare
Age: 4th 5th decade; M:F = 2:1

  • usually asymptomatic

  • @ Vertebra (28% of all skeletal hemangiomas)

    Incidence: in 5 11% of all autopsies; multiple in 1/3
    Histo: capillary hemangioma interspersed in fatty matrix

    • The larger the degree of fat overgrowth, the less likely the lesion will be symptomatic!

      Age: >40 years; female
      Location: in lower thoracic / upper lumbar spine

    • accordion / corduroy / honeycomb vertebra = coarse vertical trabeculae with osseous reinforcement adjacent to bone resorption caused by vascular channels (also in multiple myeloma, lymphoma, metastasis)

    • bulge of posterior cortex

    • extraosseous extension beyond bony lesion into spinal canal (with cord compression) / neural foramina

    • paravertebral soft-tissue extension

    • lesion enhancement (due to hypervascularity)

      • P.100


    • CT:

      • polka-dot appearance = small punctate areas of sclerosis (= thickened vertical trabeculae)

    • MR:

      • mottled pattern of low-to-high intensity on T1WI + very-high intensity on T2WI depending on degree of adipose tissue (CHARACTERISTIC)

      Cx: vertebral collapse (unusual), spinal cord compression

  • @ Calvarium (20% of all hemangiomas)

    Location: frontal / parietal region
    Site: diploe

    • <4 cm round osteolytic lesion with sunburst / weblike / spoke-wheel appearance of trabecular thickening

    • expansion of outer table to a greater extent than inner table producing palpable lump

  • @ Flat bones & long bones (rare)

    • ribs, clavicle, mandible, zygoma, nasal bones, metaphyseal ends of long bones (tibia, femur, humerus)

    • radiating trabecular thickening

    • bubbly bone lysis creating honeycomb / latticelike / hole-within-hole appearance

    • MR:

      • serpentine vascular channels with low signal intensity on T1WI + high signal intensity on T2WI (= slow blood flow) / low signal intensity on all sequences (= high blood flow)

    • NUC (bone / RBC-labeled scintigraphy):

      • photopenia / moderate increased activity

Soft-tissue Hemangioma

Incidence: 7% of all benign tumors; most frequent tumor of infancy + childhood
Age: primarily in children; M < F
May be associated with: Maffucci syndrome (= multiple cavernous hemangiomas + enchondromas)

  • intermittent change in size

  • painful

  • bluish discoloration of overlying skin (rare)

  • may dramatically increase in size during pregnancy

    Location: usually intramuscular; synovia (<1% of all hemangiomas); common in head and neck

  • nonspecific soft-tissue mass

  • may extend into bone creating subtle rounded / linear areas of hyperlucency (rare)

  • longitudinal / axial bone overgrowth (secondary to chronic hyperemia)

  • may contain phleboliths (30% of lesions, SPECIFIC)

  • nonspecific curvilinear / amorphous calcifications

  • may contain such large amounts of fat as to be indistinguishable from lipoma

  • CT:

    • poorly defined mass with attenuation similar to muscle

    • areas of decreased attenuation approximating subcutaneous fat (= fat overgrowth) most prominent in periphery of lesion

  • MR:

    • poorly marginated mass hypo- / isointense to muscle on T1WI

    • areas with increased signal intensity on T1WI in periphery of lesion extending into septations (= fat)

    • well-marginated markedly hyperintense mass on T2WI (increased free water content in stagnant blood) with striated / septated configuration

    • tubular structures with blood flow characteristics (flow void / inflow enhancement; marked contrast enhancement)

    • phleboliths as low-intensity areas inside lesion

    • high-signal-intensity areas on T1WI + T2WI (= hemorrhage)

    US:

    • complex mass

    • low-resistance arterial signal (occasionally)

Synovial Hemangioma

  • repetitive bleeding into joint

    Location: knee (60%), elbow (30%)
    DDx: hemophilic arthropathy (polyarticular)

Hemangiopericytoma

  • = borderline tumor with benign / locally aggressive / malignant behavior (counterpart of glomus tumor)

    Age: 4th 5th decade; M:F = 1:1
    Path: large vessels predominantly in tumor periphery
    Histo: cells packed around vascular channels containing cystic + necrotic areas; arising from cells of Zimmerman that are located around vessels

  • @ Soft tissue

    • = deep-seated well-circumscribed lesion arising in muscle

      Location: lower extremity in 35% (thigh), pelvic cavity, retroperitoneum

    • painless slowly growing mass up to 20 cm

  • @ Bone (rare)

    Location: lower extremity, vertebrae, pelvis, skull (dura similar to meningioma)

    • osteolytic lesions in metaphysis of long / flat bone

    • subperiosteal large blowout lesion (similar to aneurysmal bone cyst)

  • Angio:

    • displacement of main artery

    • pedicle of tumor feeder arteries

    • spider-shaped arrangement of vessels encircling tumor

    • small corkscrew arteries

    • dense tumor stain

    DDx: hemangioendothelioma, angiosarcoma

Hemochromatosis

= excess iron deposition in tissues (hemosiderosis) resulting in tissue injury

Primary / Idiopathic Hemochromatosis

  • = autosomal recessive genetic disorder (abnormal iron-loading gene on short arm of chromosome 6) in thalassemia, sideroblastic anemia

    Defect: increased absorption + parenchymal accumulation of dietary iron
    Organs: liver, pancreas, heart (parenchymal iron overload)
    Homozygous frequency: 1:200; M:F = 1:1
    Age: >30 years (M), usually after menopause (F); females protected by menstruation

    • P.101


  • cirrhosis (frequently present at time of diagnosis)

  • bronzed diabetes (50%) = insulin-dependent diabetes (excess intracellular iron reduces function of beta islet cells while reserve capacity of exocrine function is not exceeded by toxic effects of iron)

  • congestive cardiomyopathy (myocardial muscle accumulates toxic levels of intracellular iron)

  • skin pigmentation

  • hypogonadism + decreased libido (2 to pituitary dysfuncton)

  • slowly progressive arthritic symptoms (30%)

  • increased serum iron + ferritin level (nonspecific)

  • transferrin saturation + serum ferritin assay (specific)

  • @ Skeleton

    Distribution: most commonly in hands (metacarpal heads, particularly 2nd + 3rd MCP joints), carpal (30 50%) + proximal interphalangeal joints, knees, hips, elbows

    • generalized osteoporosis

    • small subchondral cystlike rarefactions with fine rim of sclerosis (metacarpal heads)

    • arthropathy in 50% (iron deposition in synovium)

    • uniform symmetric joint space narrowing (unusual for degenerative joint disease)

    • enlargement of metacarpal heads:

      • hook-like osteophytes on radial aspect of metacarpal heads (CHARACTERISTIC)

    • chondrocalcinosis in >60%, knees most commonly affected

      • calcium pyrophosphate deposition (inhibition of pyrophosphatase enzyme within cartilage which hydrolyzes pyrophosphate to soluble orthophosphate)

      • calcification of triangular cartilage of wrist, menisci, annulus fibrosus, ligamentum flavum, symphysis pubis, Achilles tendon, plantar fascia

  • @ Brain

    • marked loss in signal intensity of anterior lobe of pituitary gland (iron deposition)

  • @ Abdomen

    • decreased T2 signal intensity in liver, pancreas

    • normal T2 signal intensity of spleen on T2WI + T2*WI

Dx: liver biopsy with hepatic iron index > 2 (= iron concentration in mol/g of dry weight divided by patient's age in years)
Cx: hepatoma in 14% (iron stimulates growth of neoplasms)
Prognosis: death from CHF (30%), death from hepatic failure (25%), death from HCC (in up to 33%)
Rx: (1) Phlebotomy (return of life expectancy to normal if instituted prior to complications)
(2) Screening of family members (gene can be located by human leukocyte antigen typing)
DDx: Pseudogout (no arthropathy)
(2) Psoriatic arthritis (skin + nail changes)
(3) Osteoarthritis (predominantly distal joints in hands)
(4) Rheumatoid arthritis
(5) Gout (may also have chondrocalcinosis)

Secondary Hemochromatosis

= nongenetic iron overload

  • ineffective erythropoiesis: thalassemia major increased demand for iron resulting in increased absorption + retention of dietary iron

    Cx: increase in parenchymal iron

  • Bantu siderosis = parenchymal + RES iron overload due to extensive use of iron pots for cooking

Transfusional Siderosis

  • = iron overload of the RES (NOT a form of secondary hemochromatosis); iron less toxic [siderosis = exposure to excess iron]

    Pathophysiology: large number of damaged erythrocytes from blood transfusions are incorporated into RES cells + undergo lysis with liberation of iron from hemoglobin (extravascular hemolysis)
    Organs of RES: Kupffer cells, spleen, bone marrow

  • decreased signal intensity of liver + spleen on T2WI

    Iron storage capacity of RES: 10 g (equivalent to 40 units of packed RBCs)

Hemolytic Anemia

Cause:

  • Anemia:

    • Sickle cell disease

    • Thalassemia

    • Hereditary spherocytosis

    • Paroxysmal nocturnal hemoglobulinuria

  • Chronic / severe blood loss

  • Marrow replacement by neoplastic cells

  • Treatment with granulocyte-macrophage colony-stimulating factor

Reconversion = recruitment of yellow marrow for hematopoiesis once hematopoietic capacity of existing red marrow stores is exceeded

Order of reconversion: spine > flat bones > skull > long bones (proximal > distal metaphysis > diaphysis > epi- / apophyses)

MR:

  • signal intensity of hyperplastic marrow similar to muscle on T1WI + T2WI + STIR

  • red marrow hypointense relative to fat on T2WI

  • low signal intensity of renal cortex on T1WI + T2WI due to hemosiderin deposition (after intravascular hemolysis)

Cx:

  • Hemosiderosis (histologic term of iron deposition in tissue) = excess iron in cells of RES 2 to repeated blood transfusions

    • magnetic susceptibility effects of hemosiderin produce hypointense marrow on T2WI (+ T1WI if hemosiderosis severe)

  • Medullary infarction (common in sickle cell disease)

DDx: leukemia (hyperintense on STIR)

Hemophilia

= X-linked deficiency / functional abnormality of coagulation factor VIII (= hemophilia A) in >80% / factor IX (= hemophilia B = Christmas disease)

Incidence: 1:10,000 males

Hemophilic Arthritis

P.102


Hemophilic Arthropathy (most common)

Cause: repeated bleeding into synovial joint
Path: pannus formation erodes cartilage with loss of subchondral bone plate and formation of subarticular cysts
Histo: synovial hyperplasia, chronic inflammatory changes, fibrosis, siderosis of synovial membrane
Age: 1st and 2nd decade

  • tense red warm joint with decreased range of motion (muscle spasm)

  • fever, elevated WBC (DDx: septic arthritis)

    Location: knee > ankle > elbow > shoulder; commonly bilateral although bleeding episodes tend to recur within same joint

  • joint effusion (= hemarthrosis)

  • enlargement of epiphysis (secondary to synovial inflammation + hyperemia)

  • juxtaarticular osteoporosis (secondary to synovial inflammation + hyperemia)

  • joint space narrowing (particularly patella) secondary to cartilaginous denudation

  • erosion of articular surface with multiple subchondral cysts

  • sclerosis + osteophytosis (secondary to superimposed degenerative joint disease)

  • @ Knee

    • squared patella

    • widening of intercondylar notch

    • flattening of condylar surface

    • medial slanting of tibiotalar joint

  • MR:

    • low signal intensity of hypertrophied synovial membrane on all pulse sequences (due to magnetic susceptibility effect of hemosiderin)

    • varying intensity of subarticular defects (depending on substrate: fluid / soft tissue / hemosiderin)

Hemophilic Pseudotumor (1 2%)

  • = posthemorrhagic cystic swelling within muscle + bone characterized by pressure necrosis + destruction

  • (a) juvenile form = usually multiple intramedullary expansile lesions without soft-tissue mass in small bones of hand / feet (before epiphyseal closure)

  • (b) adult form = usually single intramedullary expansile lesion with large soft-tissue mass in ilium / femur

  • (c) soft-tissue involvement of retroperitoneum (psoas muscle), bowel wall, renal collecting system

  • mixed cystic expansile lesion

  • bone erosion + pathologic fracture

  • CT:

    • sometimes encapsulated mass containing areas of low attenuation + calcifications

  • MR:

    • hemorrhage of varying age

Cx: joint contracture (after repeated bleeding into muscle)
N.B.: Needle aspiration / biopsy / excision may cause fistulae / infection / uncontrolled bleeding!
Rx: palliative radiation therapy (destroys vessels prone to bleed) + transfusion of procoagulation factor concentrate

Hereditary hyperphosphatasia

  • = JUVENILE PAGET DISEASE

  • = rare autosomal recessive disease with sustained elevation of serum alkaline phosphatase, especially in individuals of Puerto Rican descent

    Histo: rapid turnover of lamellar bone without formation of cortical bone; immature woven bone is rapidly laid down, but simultaneous rapid destruction prevents normal maturation
    Age: 1st 3rd year; usually stillborn

  • rapid enlargement of calvarium + long bones

  • dwarfism

  • cranial nerve deficit (blind, deaf)

  • hypertension

  • frequent respiratory infections

  • pseudoxanthoma elasticum

  • elevated alkaline phosphatase

  • deossification = decreased density of long bones with coarse trabecular pattern

  • metaphyseal growth deficiency

  • wide irregular epiphyseal lines (resembling rickets in childhood), persistent metaphyseal defects (40% of adults)

  • bowing of long bones + fractures with irregular callus

  • widened medullary canal with cortical thinning (cortex modeled from trabecular bone)

  • skull greatly thickened with wide tables, cotton wool appearance

  • vertebra plana

  • OB-US:

    • diagnosis suspected in utero in 20%

    Cx: pathologic fractures; vertebra plana universalis
    DDx: (1) Osteogenesis imperfecta
    (2) Polyostotic fibrous dysplasia
    (3) Paget disease (> age 20, not generalized)
    (4) Pyle disease (spares midshaft)
    (5) van Buchem syndrome (only diaphyses > age 20, no long-bone bowing)
    (6) Engelmann syndrome (lower limbs)

Hereditary Multiple Diaphyseal Sclerosis

  • = RIBBING DISEASE

    Herniation Pit on AP and LAT Radiographs

    • P.103


  • = autosomal recessive disorder similar to Engelmann-Camurati disease

    Age: after puberty

  • mild neuromuscular symptoms

    Location: long bones only

  • unilateral asymmetric / asynchronous bilateral sclerosis

    DDx: Engelmann-Camurati disease (begins in childhood, severe neuromuscular symptoms, symmetric bilateral sclerosis of long bones, skull involved)

Hereditary Spherocytosis

  • = autosomal dominant congenital hemolytic anemia

    Age: anemia begins in early infancy to late adulthood

  • rarely severe anemia

  • jaundice

  • spherocytes in peripheral smear

  • bone changes rare (due to mild anemia); long bones rarely affected

  • widening of diploe with displacement + thinning of outer table

  • hair-on-end appearance

    Rx: splenectomy corrects anemia even though spherocytemia persists

    • improvement in skeletal alterations following splenectomy

Herniation Pit

  • = SYNOVIAL HERNIATION PIT = CONVERSION DEFECT

  • = ingrowth of fibrous + cartilaginous elements from adjacent joint through perforation in cortex

    Histo: fibroalveolar tissue
    Age: usually in older individuals

  • may be symptomatic

  • no clinical significance

    Location: anterior superolateral aspect of proximal femoral neck; uni- or bilateral
    Site: subcortical

  • well-circumscribed round lucency

  • usually <1 cm in diameter; may enlarge over time

  • reactive thin sclerotic border

  • hyperintense area on T2WI (= fluid signal intensity)

  • bone scan may be positive

Holt-Oram Syndrome

Autosomal dominant; M < F

Associated with CHD: secundum type ASD (most common), VSD, persistent left SVC, tetralogy, coarctation

  • intermittent cardiac arrhythmia

  • bradycardia (50 60/min)

    Location: upper extremity only involved; symmetry of lesions is the rule; left side may be more severely affected

  • aplasia / hypoplasia of radial structures: thumb, 1st metacarpal, carpal bones, radius

  • fingerized hypoplastic thumb / triphalangeal thumb

  • slender elongated hypoplastic carpals + metacarpals

  • hypoplastic radius; absent radial styloid

  • shallow glenoid fossa (voluntary dislocation of shoulder common)

  • hypoplastic clavicula

  • high arched palate

  • cervical scoliosis

  • pectus excavatum

Homocystinuria

Autosomal recessive disorder

Etiology: cystathionine B synthetase deficiency results in defective methionine metabolism with accumulation of homocystine + homocysteine in blood and urine; causes defect in collagen / elastin structure

  • thromboembolic phenomena due to stickiness of platelets

  • ligamentous laxity

  • downward + inward dislocation of lens (DDx: upward + outward dislocation in Marfan syndrome)

  • mild / moderate mental retardation

  • crowding of maxillary teeth and protrusion of incisors

  • malar flush

  • arachnodactyly in 1/3 (DDx: Marfan syndrome)

  • microcephaly

  • enlarged paranasal sinuses

  • osteoporosis of vertebrae (biconcave / flattened / widened vertebrae)

  • scoliosis

  • pectus excavatum / carinatum (75%)

  • osteoporosis of long bones (75%) with bowing + fracture

  • children: metaphyseal cupping (50%); enlargement of ossification centers in 50% (knee, carpal bones); epiphyseal calcifications (esp. in wrist, resembling phenylketonuria); delayed ossification

  • Harris lines = multiple growth lines

  • genu valgum, coxa valga, coxa magna, pes cavus

    Differences between Homocystinuria and Marfan

      Homocystinuria Marfan Syndrome
    Inheritance autosomal recessive autosomal dominant
    Biochemical defect cystathionine synthetase not known
    Osteoporosis yes no
    Spine biconcave vertebrae scoliosis
    Lens dislocation downward upward
    Arachnodactyly 33% 100%

    • P.104


  • premature vascular calcifications

    Prognosis: death from occlusive vascular disease / minor vascular trauma

Hyperparathyroidism

  • = uncontrolled production of parathyroid hormone

    Age: 3rd 5th decade; M:F = 1:3
    Histo: decreased bone mass secondary to increased number of osteoclasts, increased osteoid volume (defect in mineralization), slightly increased number of osteoblasts

  • increase in parathyroid hormone (100%)

  • increase in serum alkaline phosphatase (50%)

  • elevation of serum calcium (due to accelerated bone turnover and increased calcium absorption) + decrease in serum phosphate (30%)

  • hypotonicity of muscles, weakness, constipation, difficulty in swallowing, duodenal / gastric peptic ulcer disease (secondary to hypercalcemia)

  • polyuria, polydipsia (hypercalciuria + hyperphosphaturia)

  • renal colic + renal insufficiency (nephrocalculosis + nephrocalcinosis)

  • rheumatic bone pain + tenderness (particularly at site of brown tumor), pathologic fracture secondary to brown tumor

  • BONE RESORPTION

    • subperiosteal (most constant + specific finding; virtually PATHOGNOMONIC of hyperparathyroidism):

      • lacelike irregularity of cortical margin; may progress to scalloping / spiculation (pseudoperiostitis)

        Site: phalangeal tufts (earliest involvement), radial aspect of middle phalanx of 2nd + 3rd finger beginning in proximal metaphyseal region (early involvement), bandlike zone of resorption in middle / base of terminal tuft, distal end of clavicles, medial tibia plateau, medial humerus neck, medial femoral neck, distal ulna, superior + inferior margins of ribs in midclavicular line, lamina dura of skull and teeth

    • subchondral:

      • pseudowidening of joint space

      • collapse of cortical bone + overlying cartilage with development of erosion, cyst, joint narrowing (similar to rheumatoid arthritis)

        Site: DIP joint (most commonly 4th + 5th digit), MCP joint, PIP joint, distal clavicle, acromioclavicular joint (clavicular side), pseudowidening of sacroiliac joint (iliac side), sternoclavicular joint, symphysis pubis, scalloping of posterior surface of patella, Schmorl nodes; typically polyarticular

    • cortical (due to osteoclastic activity within haversian canal):

      • intracortical tunneling

      • scalloping along inner cortical surface (endosteal resorption)

    • trabecular:

      • spotty deossification with indistinct + coarse trabecular pattern

      • granular salt and pepper skull

      • loss of distinction between inner and outer table

      • ground-glass appearance

    • subligamentous:

      • bone resorption with smooth scalloped / irregular ill-defined margins

        Site: inferior surface of calcaneus (long plantar tendons + aponeurosis), inferior aspect of distal clavicle (coracoclavicular ligament), greater trochanter (hip abductors), lesser trochanter (iliopsoas), anterior inferior iliac spine (rectus femoris), humeral tuberosity (rotator cuff), ischial tuberosity (hamstrings), proximal extensor surface of ulna (anconeus), posterior olecranon (triceps)

  • BONE SOFTENING

    • basilar impression of skull

    • wedged vertebrae, kyphoscoliosis, biconcave vertebral deformities

    • bowing of long bones

    • slipped capital femoral epiphysis

  • BROWN TUMOR

    • = OSTEOCLASTOMA

      Cause: PTH-stimulated osteoclastic activity (more frequent in 1 HPT; in 1.5% of 2 HPT)
      Path: localized replacement of bone by vascularized fibrous tissue (osteitis fibrosa cystica) containing giant cells; lesions may become cystic following necrosis + liquefaction
      Location: jaw, pelvis, rib, metaphyses of long bones (femur), facial bones, axial skeleton
      Site: often eccentric / cortical; frequently solitary

    • expansile lytic well-marginated cystlike lesion (DDx: giant cell tumor) without adjacent reactive bone formation

    • endosteal scalloping

    • destruction of midportions of distal phalanges with telescoping

  • OSTEOSCLEROSIS

    • More frequent in 2 HPT

      Cause: ? PTH-stimulated osteoblastic activity,? role of calcitonin (poorly understood)
      Site: strong predilection for axial skeleton, pelvis, ribs, clavicles, metaphysis + epiphysis of appendicular skeleton

    • rugger jersey spine

  • SOFT-TISSUE CALCIFICATION

    More frequent in 2 HPT; metastatic calcification when Ca P product >70 mg/dL

    • cornea, viscera (lung, stomach, kidney)

    • periarticular in hip, knee, shoulder, wrist

    • arterial tunica media (resembling diabetes mellitus)

    • chondrocalcinosis (15 18%) = calcification of hyaline / fibrous cartilage in menisci, wrist, shoulder, hip, elbow

  • EROSIVE ARTHROPATHY

    • asymptomatic

    • simulates rheumatoid arthritis with preserved joint spaces

  • PERIOSTEAL NEW-BONE FORMATION

    Cause: PTH-stimulation of osteoblasts
    Site: pubic ramus along iliopectineal line (most frequent), humerus, femur, tibia, radius, ulna, metacarpals, metatarsals, phalanges

    • linear new bone paralleling cortical surface; may be laminated; often separated from cortex by radiolucent zone

      • P.105


    • increase in cortical thickness (if periosteal reaction becomes incorporated into adjacent bone)

Sequelae:

  • Renal stones / nephrocalcinosis (70%)

  • Increased osteoblastic activity (25%)

    • increased alkaline phosphatase

      • osteitis fibrosa cystica

        • subperiosteal bone resorption + cortical tunneling

        • brown tumors (primary HPT)

      • bone softening

        • fractures

  • Peptic ulcer disease (increased gastric secretion from gastrinoma)

  • Calcific pancreatitis

  • Soft-tissue calcifications (2 HPT)

  • Marginal joint erosions + subarticular collapse (DIP, PIP, MCP)

Primary Hyperparathyroidism

  • = pHPT = 1 HPT = hypercalcemia due to uncontrolled secretion of parathormone by one / more hyperfunctioning parathyroid glands featuring

    • brown tumor

    • chondrocalcinosis (20 30%)

  • requires surgical Rx

Incidence: 25:100,000 per year; incidence of bone lesions in HPT is 25 40%

Etiology:

  • Parathyroid adenoma (87%): single (80%); multiple (7%)

  • Parathyroid hyperplasia (10%): chief cell (5%); clear cell (5%)

  • Parathyroid carcinoma (3%)

Histo: increased number of osteoclasts, increased osteoid volume (defect in mineralization), slightly increased osteoblasts = decreased bone mass
Age: 3rd 5th decade; M:F = 1:3

Associated with:

  • Wermer syndrome = MEA I (+ pituitary adenoma + pancreatic islet cell tumor)

  • Sipple syndrome = MEA II (+ medullary thyroid carcinoma + pheochromocytoma)

X-RAY (skeletal involvement in 10 20%):

  • thin cortices with lacy cortical pattern (subperiosteal bone resorption)

    Differences between 1 and 2 HPT

    Skeletal Findings 1 HPT 2 HPT
    Osteopenia, diffuse present present
    Osteosclerosis, regional / diffuse rare common
    Bone resorption common common
    Brown tumor common less common
    Soft-tissue calcification not infrequent common
    Chondrocalcinosis not infrequent rare

  • brown tumor (particularly in jaw + long bones)

  • osteitis cystica fibrosa (= intertrabecular fibrous connective tissue)

NUC:

  • normal bone scan in 80%

  • foci of abnormal uptake: calvarium (especially periphery), mandible, sternum, acromioclavicular joint, lateral humeral epicondyles, hands

  • increased uptake in brown tumors

  • extraskeletal uptake: cornea, cartilage, joint capsules, tendons, periarticular areas, lungs, stomach

  • normal renal excretion [except in stone disease / calcium nephropathy (10%)]

Rx: pathologic glands identified by experienced surgeons in 90 95% on initial neck exploration (ectopic + supernumerary glands often overlooked at operation; recurrent hypercalcemia in 3 10%)

Surgical risk for repeat surgery:

6.6% recurrent laryngeal nerve injury
20.0% permanent hypoparathyroidism
<1.0% perioperative mortality

Secondary Hyperparathyroidism

  • = sHPT = 2 HPT = diffuse / adenomatous hyperplasia of all four parathyroid glands as a compensatory mechanism in any state of hypocalcemia featuring (1) soft-tissue calcifications (2) osteosclerosis

  • requires medical Rx

    Etiology:

    • renal osteodystrophy (renal insufficiency + osteomalacia / rickets)

    • calcium deprivation, maternal hypoparathyroidism, pregnancy, hypovitaminosis D

    • rise in serum phosphate leading to decrease in calcium by feedback mechanism

  • low to normal calcium levels

  • Ca2+ PO42- solubility product often exceeded

  • NUC:

    • superscan in 2 HPT:

      • absent kidney sign

      • increased bone-to-soft tissue uptake ratio

      • increased uptake in calvarium, mandible, acromioclavicular region, sternum, vertebrae, distal third of long bones, ribs

    • diffuse Tc-99m MDP uptake in lungs (60%)

Tertiary Hyperparathyroidism

  • = tHPT = 3 HPT = development of autonomous PTH adenoma in patients with chronically overstimulated hyperplastic parathyroid glands (renal insufficiency + prolonged renal dialysis)

  • requires surgical Rx

    Clue: (a) intractable hypercalcemia
    (b) inability to control osteomalacia by vitamin D administration

Ectopic Parathormone Production

= pseudohyperparathyroidism as paraneoplastic syndrome in bronchogenic carcinoma + renal cell carcinoma

P.106


Hypertrophic Osteoarthropathy

  • = HYPERTROPHIC PULMONARY OSTEOARTHROPATHY (HPO) = Marie-Bamberger disease

  • = paraneoplastic syndrome

Etiology: (1) Release of vasodilators which are not metabolized by lung
(2) Increased flow through AV shunts
(3) Reflex peripheral vasodilation (vagal impulses)
(4) Hormones: estrogen, growth hormone, prostaglandin
Histo: round cell infiltration of the outer fibrous layer of periosteum followed by new bone proliferation

  • THORACIC CAUSES

    • malignant tumor (0.7 12%): bronchogenic carcinoma (88%), mesothelioma, lymphoma, pulmonary metastasis from osteogenic sarcoma, melanoma, renal cell carcinoma, breast cancer

      • 4 17% of patients with bronchogenic carcinoma ma develop HPO!

    • benign tumor: benign pleural fibroma, tumor of ribs, thymoma, esophageal leiomyoma, pulmonary hemangioma, pulmonary congenital cyst

    • chronic infection / inflammation: pulmonary abscess, bronchiectasis, blastomycosis, TB (very rare); cystic fibrosis, interstitial fibrosis

    • cyanotic congenital heart disease with R-to-L shunt

  • EXTRATHORACIC CAUSES (less common)

    • GI tract: ulcerative colitis, amebic + bacillary dysentery, intestinal TB, Whipple disease, Crohn disease, gastric ulcer, bowel lymphoma, gastric carcinoma

    • liver disease: biliary + alcoholic cirrhosis, posthepatic cirrhosis, chronic active hepatitis, bile duct carcinoma, benign bile duct stricture, amyloidosis, liver abscess

    • undifferentiated nasopharyngeal carcinoma, pancreatic carcinoma, chronic myelogenous leukemia

  • burning pain, painful swelling of limbs, and stiffness of joints: ankles (88%), wrists (83%), knees (75%), elbows (17%), shoulders (10%), fingers (7%)

  • peripheral neurovascular disorders: local cyanosis, areas of increased sweating, paresthesia, chronic erythema, flushing + blanching of skin

  • hippocratic fingers + toes (clubbing)

  • hypertrophy of extremities (soft-tissue swelling)

Location: tibia + fibula (75%), radius + ulna (80%), proximal phalanges (60%), femur (50%), metacarpus + metatarsus (40%), humerus + distal phalanges (25%), pelvis (5%); unilateral (rare)
Spine, pelvis, ribs usually spared!
Site: in diametaphyseal regions

  • cortical thickening

  • lamellar periosteal proliferation of new bone, at first smooth then undulating + rough

    Site: most conspicuous on concavity of long bones (dorsal + medial aspects)

  • soft-tissue swelling ( clubbing ) of distal phalanges

  • Bone scan (reveals changes early with greater sensitivity + clarity):

    • parallel track / double stripe / tramline sign = patchy linear diffusely increased symmetric uptake along cortical margins of metaphysis + diaphysis of tubular bones (= periostitis)

    • increased periarticular uptake (= synovitis)

    • scapular involvement in 2/3

    • mandible maxilla abnormal in 40%

Prognosis: treatment of underlying condition leads to remission of symptoms often within 24 hours + regression of radiographic findings in months
DDx: (1) Pachydermoperiostosis (self-limited, adolescence, autosomal dominant, M>F)
(2) Metastases (axial skeleton, focal asymmetric distribution)
(3) Chronic vascular insufficiency
(4) Thyroid acropachy
(5) Hypervitaminosis A

Hypervitaminosis A

Age: usually infants + children
Cause: overdosing vitamin A, 13-cis-retinoic acid (treatment for neuroblastoma)

  • anorexia, irritability

  • loss of hair, dry skin, pruritus, fissures of lips

  • jaundice, enlargement of liver

  • separation of cranial sutures secondary to hydrocephalus (coronal > lambdoid) in children <10 years of age, may appear within a few days

  • symmetrical solid periosteal new-bone formation along shafts of long + short bones (ulna, clavicle)

  • premature epiphyseal closure + thinning of epiphyseal plates

  • accelerated growth

  • tendinous, ligamentous, pericapsular calcifications

  • changes usually disappear after cessation of vitamin A ingestion

    DDx: infantile cortical hyperostosis (mandible involved)

Hypervitaminosis D

  • = excessive ingestion of vitamin D (large doses act like parathormone)

  • loss of appetite, diarrhea, drowsiness, headaches

  • polyuria, polydipsia, renal damage

  • convulsions

  • excessive phosphaturia (parathormone decreases tubular absorption)

  • hypercalcemia + hypercalciuria; anemia

  • deossification

  • widening of provisional zone of calcification

  • cortical + trabecular thickening

  • alternating bands of increased + decreased density near / in epiphysis (zone of provisional calcification)

  • vertebra outlined by dense band of bone + adjacent radiolucent line within

  • dense calvarium

  • metastatic calcinosis in

    • arterial walls (between age 20 and 30)

    • kidneys = nephrocalcinosis

    • periarticular tissue (puttylike)

    • premature calcification of falx cerebri (most consistent sign!)

Hypoparathyroidism

  • tetany = hypocalcemic neuromuscular excitability (numbness, cramps, carpopedal spasm, laryngeal stridor, generalized convulsions)

    • P.107


  • hypocalcemia + hyperphosphatemia

  • normal / low serum alkaline phosphatase

  • premature closure of epiphyses

  • hypoplasia of tooth enamel + dentine; blunting of roots

  • generalized increase in bone density in 9%:

    • localized thickening of skull

    • sacroiliac sclerosis

    • bandlike density in metaphysis of long bones (25%), iliac crest, vertebral bodies

    • thickened lamina dura (inner table) + widened diploe

    • deformed hips with thickening + sclerosis of femoral head + acetabulum

  • @ Soft tissue

    • intracranial calcifications in basal ganglia, choroid plexus, occasionally in cerebellum

    • calcification of spinal and other ligaments

    • subcutaneous calcifications

    • ossification of muscle insertions

    • ectopic bone formation

Idiopathic Hypoparathyroidism

  • = rare condition of unknown cause

  • round face, short dwarflike, obese

  • mental retardation

  • cataracts

  • dry scaly skin, atrophy of nails

  • dental hypoplasia (delayed tooth eruption, impaction of teeth, supernumerary teeth)

Secondary Hypoparathyroidism

  • = accidental removal / damage to parathyroid glands in thyroid surgery / radical neck dissection (5%); I-131 therapy (rare); external beam radiation; hemorrhage; infection; thyroid carcinoma; hemochromatosis (iron deposition)

Hypophosphatasia

= autosomal recessive congenital disease with low activity of serum-, bone-, liver-alkaline phosphatase resulting in poor mineralization (deficient generation of bone crystals)

Incidence: 1:100,000
Histo: indistinguishable from rickets

  • phosphoethanolamine in urine as precursor of alkaline phosphatase

  • normal serum calcium + phosphorus

  • GROUP I = neonatal = congenital lethal form

    • marked demineralization of calvarium ( caput membranaceum = soft skull)

    • lack of calcification of metaphyseal end of long bones

    • streaky irregular spotty margins of calcification

    • cupping of metaphysis

    • angulated shaft fractures with abundant callus formation

    • short poorly ossified ribs

    • poorly ossified vertebrae (especially neural arches)

    • small pelvic bones

  • OB-US:

    • high incidence of intrauterine fetal demise

    • increased echogenicity of falx (enhanced sound transmission secondary to poorly mineralized calvarium)

    • poorly mineralized short bowed tubular bones + multiple fractures

    • poorly mineralized spine

    • short poorly ossified ribs

    • polyhydramnios

    Prognosis: death within 6 months

  • GROUP II = juvenile severe form

    • onset of symptoms within weeks to months

    • moderate / severe dwarfism

    • delayed weight bearing

    • resembles rickets

    • separated cranial sutures; craniostenosis in 2nd year

    Prognosis: 50% mortality

  • GROUP III = adult mild form

    • recognized later in childhood / adolescence / adulthood

    • dwarfism

    • clubfoot, genu valgum

    • demineralization of ossification centers (at birth / 3 4 months of age):

    • widened metaphyses

    • wormian bones

    Prognosis: excellent; after 1 year no further progression

  • GROUP IV = latent form of heterozygous state

    • normal / borderline levels of alkaline phosphatase

    • patients are small for age

    • disturbance of primary dentition

    • bone fragility + healed fractures

    • enlarged chondral ends of ribs

    • metaphyseal notching of long bones

    • Erlenmeyer flask deformity of femur

Hypothyroidism

Hypothyroidism during Childhood = Cretinism

Frequency: 1:4,000 live births have congenital hypothyroidism
Cause: sporadic hypoplasia / ectopia of thyroid

  • delayed skeletal maturation (appearance + growth of ossification centers, epiphyseal closure)

  • fragmented stippled epiphyses

  • wide sutures / fontanels with delayed closure

  • delayed dentition

  • delayed / decreased pneumatization of sinuses + mastoids

  • hypertelorism

  • dense vertebral margins

  • demineralization

  • hypoplastic phalanges of 5th finger

  • MR:

    • reduced myelination of brain (usually beginning during midgestation)

  • OB-US:

    • fetal goiter (especially in hyperthyroid mothers treated with methimazole / propylthiouracil / I-131)

Hypothyroidism during Adulthood

  • calvarial thickening / sclerosis

  • wedging of dorsolumbar vertebral bodies

  • coxa vara with flattened femoral head

  • premature atherosclerosis

  • No skeletal changes with adult onset!

Differences between Various Types of Hypothyroidism

  HypoPT Pseudo HypoPT Pseudopseudo HypoPT
Serum Ca
Serum P
AlkaPhos or or
Response to PTH-Injection
Urine AMP  
Urine P  
Plasma AMP  

P.108


Infantile Cortical Hyperostosis

  • = CAFFEY DISEASE

  • = uncommon self-limiting proliferative bone disease of infancy; remission + exacerbations are common

    Cause: ? infectious;? autosomal dominant with variable expression + incomplete penetrance / sporadic occurrence (rare)
    Age: <6 months, reported in utero; M:F = 1:1
    Histo: inflammation of periosteal membrane, proliferation of osteoblasts + connective tissue cells, deposition of immature bony trabeculae

  • sudden, hard, extremely tender soft-tissue swellings over bone

  • irritability, fever

  • elevated ESR, increased alkaline phosphatase

  • leukocytosis, anemia

    Location: mandible (80%) > clavicle > ulna + others (except phalanges + vertebrae + round bones of wrists and ankles)
    Site: hyperostosis affects diaphysis of tubular bones asymmetrically, epiphyses spared

  • massive periosteal new-bone formation + perifocal soft-tissue swelling

  • double-exposed ribs

  • narrowing of medullary space (= proliferation of endosteum)

  • bone expansion with remodeling of old cortex

    Prognosis: usually complete recovery by 30 months
    Rx: mild analgesics, steroids

Chronic Infantile Hyperostosis

  • disease may persist or recur intermittently for years

  • delayed muscular development, crippling deformities

  • bowing deformities, osseous bridging, diaphyseal expansion

    DDx: (1) Hypervitaminosis A (rarely <1 year of age)
    (2) Periostitis of prematurity
    (3) Healing rickets
    (4) Scurvy (uncommon <4 months of age)
    (5) Syphilis (focal destruction)
    (6) Child abuse
    (7) Prostaglandin administration (usually following 4 6 weeks of therapy)
    (8) Osteomyelitis
    (9) Leukemia
    (10) Neuroblastoma
    (11) Kinky hair syndrome
    (12) Hereditary hyperphosphatasia

Iron Deficiency Anemia

Age: infants affected
Cause: (1) inadequate iron stores at birth
(2) deficient iron in diet
(3) impaired gastrointestinal absorption of iron
(4) excessive iron demands from blood loss
(5) polycythemia vera (6) cyanotic CHD

  • widening of diploe + thinning of tables with sparing of occiput (no red marrow)

  • hair-on-end appearance of skull

  • osteoporosis in long bones (most prominent in hands)

  • absence of facial bone involvement

Jaccoud Arthropathy

After subsidence of frequent severe attacks of rheumatic fever

Path: periarticular fascial + tendon fibrosis without synovitis

  • rheumatic valve disease

Location: primarily involvement of hands; occasionally in great toe

  • muscular atrophy

  • periarticular swelling of small joints of hands + feet

  • ulnar deviation + flexion of MCP joints most marked in 4th + 5th finger

  • NO joint narrowing / erosion

Klinefelter Syndrome

47, XXY (rarely XXYY) chromosomal abnormality

Incidence: 1:750 live births (probably commonest chromosomal aberration)

  • testicular atrophy (hyalinization of seminiferous tubules) = small / absent testes, sterility (azoospermia)

  • eunuchoid constitution: gynecomastia; paucity of hair on face + chest; female pubic escutcheon

  • mild mental retardation

  • high level of urinary gonadotropins + low level of 17-ketosteroids after puberty

  • NO distinctive radiological findings!

  • may have delayed bone maturation

  • failure of frontal sinus to develop

  • small bridged sella turcica

  • scoliosis, kyphosis

  • coxa valga

  • metacarpal sign (short 4th metacarpal)

  • accessory epiphyses of 2nd metacarpal bilaterally

47, XXX = Superfemale Syndrome

  • usually over 6 feet tall; subnormal intelligence; frequently antisocial behavior

Klippel-Trenaunay Syndrome

  • = sporadic (nonhereditary) rare mesodermal abnormality that usually affects a single lower limb characterized by a triad of:

    • port-wine nevus = unilateral large flat infiltrative cutaneous capillary hemangioma often in dermatomal distribution on affected limb; may fade in 2nd 3rd decade

      • P.109


    • gigantism = overgrowth of distal digits / entire extremity (especially during adolescent growth spurt) involving soft-tissue + bone

    • varicose veins on lateral aspect of affected limb; usually ipsilateral to hemangioma

  • Pathogenesis:

    • superficial lateral venous channel of large caliber thought to represent the fetal lateral limb bud vein that has failed to regress; tissue overgrowth is secondary to impaired venous return

    Age: usually in children; M:F = 1:1
    Associated with: polydactyly, syndactyly, clinodactyly, oligodactyly, ectrodactyly, congenital dislocation of hip
    hemangiomas of colon / bladder (3 10%)
    spinal hemangiomas + AVMs
    hemangiomas in liver / spleen
    lymphangiomas of limb
    Location: lower extremity (10 15 more common than upper extremity); bilateral in <5%; extension into trunk may occur

  • extremity pain

  • spontaneous cutaneous hemorrhage

  • chronic venous insufficiency

  • cutaneous lymphatic vesicles, lymphorrhea

  • elongation of bones:

    • leg length discrepancy

    • increased metatarsal / metacarpal + phalangeal size

  • cortical thickening

  • soft-tissue hypertrophy (at birth / later in life)

  • punctate calcifications (phleboliths) in pelvis (bowel wall, urinary bladder)

  • pulmonary vein varicosities

  • cystic lung lesions

  • Venogram:

    • extensive dilation of superficial veins

    • enlarged perforating veins

    • aplasia / hypoplasia of lower extremity veins (18 40%):? selective flow of contrast material up the lateral venous channel may fail to opacify the deep venous system

    • incompetent valveless collateral venous channels (? persistent lateral limb bud vein = Klippel-Trenaunay vein) arises near the ankle + extends a variable distance up the extremity + drains into deep femoral vein / iliac veins (in >66%)

  • Color Doppler US:

    • normal deep veins

  • Lymphangiography:

    • hypoplasia of lymphatic system

Cx: thrombophlebitis, deep venous thrombosis, pulmonary embolism, lymphangitis
Rx: (1) conservative: application of graded compressive stockings, pneumatic compression devices, percutaneous sclerosis of localized venous malformations / superficial varicosities
(2) surgical: epiphysiodesis, excision of soft-tissue hypertrophy, vein stripping
DDx: (1) Parke-Weber syndrome
   = congenital persistence of multiple microscopic AV fistulas + spectrum of Klippel-Trenaunay-Weber syndrome (pulsatility, thrill, bruit)
(2) Neurofibromatosis (caf -au-lait spots, axillary freckling, cutaneous neurofibromas, macrodactyly secondary to plexiform neurofibromas, wavy cortical reaction, early fusion of growth plate, limb hypertrophy not as extensive / bilateral)
(3) Beckwith-Wiedemann syndrome (aniridia, macroglossia, cryptorchidism, Wilms tumor, broad metaphyses, thickened long-bone cortex, advanced bone age, periosteal new-bone formation, hemihypertrophy)
(4) Macrodystrophia lipomatosis (hyperlucency of fat, distal phalanges most commonly affected, overgrowth ceases with puberty, usually limited to digits)
(5) Maffucci syndrome (cavernous hemangiomas, soft tissue hypertrophy, phleboliths, multiple enchondromas)

Labral Tears of Shoulder

Anterior Labral Tear

Location: anteroinferior labrum > entire anterior labrum > isolated tear of anterosuperior labrum

  • Subtypes of anteroinferior labral tears:

    • Bankart lesion

    • Anterior labroligamentous periosteal sleeve avulsion

    • Perthes lesion

  • absence / detachment of labrum

  • frayed labrum with irregular margin

DDx: (1) Middle + inferior glenohumeral ligaments closely apposed to anterior labrum
(2) Recess between anterior labrum + glenoid rim
(3) Recess between middle + inferior ligaments

Slap Lesion

  • = anterior-to-posterior lesion of the superior labrum centered at biceps tendon attachment

    Mechanism: fall on an outstretched hand (most common), anterior shoulder dislocation, sports activity with overhead arm motion

  • pain, clicking sensation

  • after fall on outstretched hand (31%) patient usually presents with SLAP III, IV, V lesion

P.110


SLAP I = fraying of superior labrum; common in elderly as a degenerative tear
SLAP II = detachment of superior biceps-labral complex from glenoid rim
DDx: superior sublabral recess (less distance between labrum + glenoid, no irregular appearance, no lateral extension of defect)
SLAP III = bucket-handle tear of superior labrum leaving biceps tendon attached to glenoid
SLAP IV = bucket-handle tear of superior labrum with tear extending into biceps tendon
SLAP V = Bankart lesion dissecting upward to involve the biceps tendon
SLAP VI = unstable radial / flap tear with separation of biceps anchor
SLAP VII = superior labral tear extending into middle glenohumeral ligament
SLAP VIII = SLAP II + entire posterior labral tear; anterior inferior labrum not involved
SLAP IX = circumferential labral tear

Superior Labrum Anterior-to-Posterior Lesions

Langerhans cell histiocytosis

  • = LCH = HISTIOCYTOSIS X (former name)

  • = poorly understood group of disorders characterized by proliferation of Langerhans cells (normally responsible for first-line immunologic defense in the skin)

Cause: uncertain (? primary proliferative disorder possibly due to defect in immunoregulation; neoplasm; virus)
Path: influx of eosinophilic leukocytes simulating inflammation; reticulum cells accumulate cholesterol + lipids (= foam cells); sheets or nodules of histiocytes may fuse to form giant cells, cytoplasm contains (? viral) Langerhans bodies
Histo: Langerhans cells are similar to mononuclear macrophages + dendritic cells as the two major types of nonlymphoid mononuclear cells involved in immune + nonimmune inflammatory response; derived from promonocytes (= bone marrow stem cell)
Age: any age, mostly presenting at 1 4 years; M:F = 1:1
Location: bone + bone marrow, lymph nodes, thymus, ear, liver and spleen, gallbladder, GI tract, endocrine system
DDx: osteomyelitis, Ewing sarcoma, leukemia, lymphoma, metastatic neuroblastoma

Clinical manifestations:

  • Localized LCH (70%) = eosinophilic granuloma

  • Disseminated LCH (30%)

    • Chronic disseminated LCH (20%) = Hand-Sch ller-Christian disease

    • Fulminant disseminated LCH (10%) = Letterer-Siwe disease

Eosinophilic Granuloma (70%)

  • = most benign variety of LCH localized to bone

    Age: 5 10 years (highest frequency); range 2 30 years; <20 years (in 75%); M:F = 3:2
    Path: bone lesions arise within medullary canal (RES)
    Histo: considerable number of eosinophils in addition to the dominant Langerhans cell constituent

  • painful tender bone lesion + soft-tissue swelling

  • fever, leukocytosis, elevated sedimentation rate

  • eosinophilia in blood + CSF

    Location: bone (in children) or lung (in adults)
    Sites: monostotic involvement in 50 75%;
    (a) flat bones: calvarium > mandible > ribs > pelvis > vertebrae (rarely posterior elements)
    (b) long bones: diaphyseal (58%) + metaphyseal (28%) + metadiaphyseal (12%) + epiphyseal (2%) in humerus, femur, tibia

  • bone lesions 1 15 cm in diameter:

    • geographic / permeative / moth-eaten configuration

    • well- / poorly defined borders

      DDx: neuroblastoma metastases, leukemia, lymphoma

  • @ Skull (50%)

    Site: diploic space of parietal bone (most commonly involved) + temporal bone (petrous ridge, mastoid)

    • round / ovoid punched-out lesion:

      DDx: venous lake, arachnoid granulation, parietal foramen, epidermoid cyst, hemangioma

      • beveled edge / hole-within-hole appearance (due to asymmetric destruction of inner + outer tables)

      • sharply marginated without sclerotic rim (DDx: epidermoid with bone sclerosis)

      • sclerotic margin during healing phase (50%)

    • button sequestrum = remnants of bone as a central bone density within a lytic lesion consisting of erosive accumulation of histiocytes

    • soft-tissue mass overlying the lytic process in calvarium (often palpable)

    • isodense homogeneously enhancing mass in hypothalamus / pituitary gland

  • @ Orbit

    • benign focal mass infiltration of orbital bones

  • @ Mastoid process

    • intractable otitis media with chronically draining ear (in temporal bone involvement)

    • destructive lesion near mastoid antrum

      DDx: mastoiditis, cholesteatoma, metastasis
      Cx: extension to middle ear may destroy ossicles leading to deafness

  • @ Jaw

    • gingival + contiguous soft-tissue swelling

    • floating teeth = destruction of alveolar bone

    • mandibular fracture

    • P.111


  • @ Axial skeleton (25%)

    • vertebra plana = coin on edge = Calv disease (6%) = collapse of vertebra (most commonly thoracic):

      • Most common cause of vertebra plana in children

      • preserved disk space

      • rare involvement of posterior elements

      • no kyphosis

    • lytic lesion in supraacetabular region

  • @ Proximal long bones (15%)

    Site: mostly diaphyseal; epiphyseal lesions are uncommon

    • expansile lytic lesion with ill-defined / sclerotic edges

    • endosteal scalloping, widening of medullary cavity

    • cortical thinning, intracortical tunneling

    • erosion of cortex + soft-tissue mass

    • laminated periosteal reaction (frequent), may show interruptions

    • may appear rapidly within 3 weeks

    • lesions respect joint space + growth plate

  • @ Lung involvement (20%)

    Incidence: 0.05 0.5:100,000 annually
    Age: peak between 20 and 40 years

    • Strong association between smoking + primary pulmonary Langerhans cell histiocytosis!

    • 3 10 mm nodules

    • reticulonodular pattern with predilection for apices

    • may develop into honeycomb lung

    • recurrent pneumothoraces (25%)

    • rib lesions with fractures (common)

    • pleural effusion, hilar adenopathy (unusual)

  • NUC:

    • negative bone scans in 35% (radiographs more sensitive)

    • bone lesions generally not Ga-67 avid

    • Ga-67 may be helpful for detecting nonosseous lesions

Prognosis: excellent with spontaneous resolution of bone lesions in 6 18 months

Hand-Sch ller-Christian Disease (20%)

  • = chronic disseminated form of LCH characterized by CLASSIC TRIAD (in 10 15%) of

    • exophthalmos (mass effect on orbital bone)

    • diabetes insipidus (basilar skull disease / direct infiltration of posterior pituitary gland)

    • destructive bone lesions (often of calvaria)

    Path: proliferation of histiocytes, may simulate Ewing sarcoma
    Age at onset: <5 years (range from birth to 40 years); M:F = 1:1

  • diabetes insipidus (30 50%) often with large lytic lesion in sphenoid bone / panhypopituitarism

  • otitis media with mastoid + inner ear invasion

  • exophthalmos (33%), sometimes with orbital wall destruction

  • generalized eczematoid skin lesions (30%)

  • ulcers of mucous membranes (gingiva, palate)

    Sites: bone, liver, spleen, lymph nodes, skin

  • @ Bone

    • osteolytic skull lesions with overlying soft-tissue nodules

    • geographic skull = ovoid / serpiginous destruction of large area

    • floating teeth with mandibular involvement

    • destruction of petrous ridge + mastoids + sella turcica

  • @ Orbit

    • diffuse orbital disease with multiple osteolytic bone lesions

  • @ Liver

    • hepatosplenomegaly (rare)

    • scattered echogenic / hypoattenuating liver granuloma

    • lymphadenopathy (may be massive)

    • gallbladder wall thickening (from infiltration)

  • @ Lung

    • cyst + bleb formation with spontaneous pneumothorax (25%)

    • ill-defined diffuse nodular infiltration often progressing to fibrosis + honeycomb lung

  • @ Thymus

    • enlarged thymus + punctate calcifications

    Prognosis: spontaneous remissions + exacerbations; fatal in 15%

Letterer-Siwe Disease (10%)

  • = acute disseminated, fulminant form of LCH characterized by wasting, pancytopenia (from bone marrow dysfunction), generalized lymphadenopathy, hepatosplenomegaly

    Incidence: 1: 2,000,000
    Age: several weeks after birth to 2 years
    Path: generalized involvement of reticulum cells; may be confused with leukemia

  • hemorrhage, purpura (secondary to coagulopathy)

  • severe progressive anemia / pancytopenia

  • intermittent fever

  • failure to grow / malabsorption + hypoalbuminemia

  • skin rash: scaly erythematous seborrhea-like brown to red papules

    Location: especially pronounced behind ears, in axillary, inguinal, and perineal areas
    Sites: liver, spleen, bone marrow, lymph nodes, skin

  • hepatosplenomegaly + lymphadenopathy (most often cervical)

  • obstructive jaundice

  • @ Bone involvement (50%):

    • widespread multiple lytic lesions; raindrop pattern in calvarium

Prognosis: rapidly progressive with 70% mortality rate

Lateral Epicondylitis

  • = Tennis Elbow = tendinitis (epicondylitis is a misnomer)

  • = chronic overuse syndrome involving origin of extensor carpi radialis brevis tendon

    Age: 35 50 years
    Cause: tennis, throwing sports, swimming, carpentry, plumbing (repetitive forearm pronation + supination with wrist extension)

  • pain + tenderness in region of lateral epicondyle radiating into forearm

    Histo: tendon microtears followed by formation of angiofibrotic hyperplasia (= noninflammatory reactive tissue)

    • P.112


  • MR (oblique coronal images):

    • focally hyperintense signal compared with muscle + less intense than fluid on all sequences

Rx: (1) conservative management: avoidance of painful activity, application of ice, NSAID
(2) splints, steroid injection
(3) excision of abnormal tissue + decortication of epicondyle + reattachment of tendon
DDx of painful elbow: injury to radial collateral ligament / extensor carpi radialis longus tendon, cartilage defect

Laurence-Moon-Biedl Syndrome

  • retardation

  • obesity

  • hypogonadism

  • craniosynostosis

  • polysyndactyly

Lead Poisoning

  • = PLUMBISM

    Path: lead concentrates in metaphyses of growing bones (distal femur > both ends of tibia > distal radius) leading to failure of removal of calcified cartilaginous trabeculae in provisional zone

  • loss of appetite, vomiting, constipation, abdominal cramps

  • peripheral neuritis (adults), meningoencephalitis (children)

  • anemia

  • lead line at gums (adults)

  • bands of increased density at metaphyses of tubular bones (only in growing bone)

  • lead lines may persist

  • clubbing if poisoning severe (anemia)

  • bone-in-bone appearance

DDx: (1) Healed rickets
(2) Normal increased density in infants <3 years of age

Leprosy

  • = HANSEN DISEASE

    Organism: Mycobacterium leprae

    Types:

    • lepromatous: in cutis, mucous membranes, viscera

    • neural: enlarged indurated nodular nerve trunks; anesthesia, muscular atrophy, neurotrophic changes

    • mixed form

  • @ Osseous changes (in 15 54% of patients)

    • specific signs:

      Location: center of distal end of phalanges / eccentric

      • ill-defined areas of decalcification, reticulated trabecular pattern, small rounded osteolytic lesions, cortical erosions

      • joint spaces preserved

      • healing phase: complete resolution / bone defect with sclerotic rim + endosteal thickening

      • nasal spine absorption + destruction of maxilla, nasal bone, alveolar ridge

      • enlarged nutrient foramina in clawlike hand

      • erosive changes of ungual tufts

    • nonspecific signs:

      • soft-tissue swelling; calcification of nerves

      • contractures / deep ulcerations

      • neurotrophic joints (distal phalanges in hands, MTP in feet, Charcot joints in tarsus)

Leukemia of Bone

  • A. CHILDHOOD

    • Most common malignancy of childhood:

      • 1/3 of all pediatric malignancies

    • Histo:

      • Acute Lymphocytic Leukemia (ALL in 75%)

        most often in children <5 years of age

        • lymph node enlargement rare

      • Acute Myelogenous Leukemia (AML)

        tends to affect older children + adolescents

        • lymph node enlargement common

    • migratory paraarticular arthralgias (25 50%) due to adjacent metaphyseal lesions (may be confused with acute rheumatic fever / rheumatoid arthritis)

    • low-grade fever, bruising, fatigue

    • bone pain (due to increased intraosseous pressure from proliferation of malignant cells)

    • elevated erythrocyte sedimentation rate, anemia

    • hepatosplenomegaly, occasionally lymphadenopathy

    • Peripheral blood smears may be negative in aleukemic form!

    • Skeletal manifestations in 50 90%:

      Location: proximal + distal metaphyses of long bones, flat bones, spine

      • Diffuse osteopenia (most common pattern)

        • diffuse demineralization of spine + long bones (= leukemic infiltration of bone marrow + catabolic protein / mineral metabolism)

        • coarse trabeculation of spongiosa (due to destruction of finer trabeculae)

        • multiple biconcave / partially collapsed vertebrae (14%)

      • Leukemic lines (40 53% in acute lymphoblastic leukemia):

        • transverse radiolucent metaphyseal bands, uniform + regular across the width of metaphysis (= leukemic infiltration of bone marrow / osteoporosis at sites of rapid growth)

          Location: large joints (proximal tibia, distal femur, proximal humerus, distal radius + ulna)

        • horizontal / curvilinear bands in vertebral bodies + edges of iliac crest

        • dense metaphyseal lines after treatment

      • Focal destruction of flat / tubular bones:

        • multiple small clearly defined ovoid / spheroid osteolytic lesions (destruction of spongiosa, later cortex) in 30 60%

        • moth-eaten appearance, sutural widening, prominent convolutional markings of skull

        • Lytic lesions distal to knee / elbow in children are suggestive of leukemia (rather than metastases)!

      • Isolated periostitis of long bones (infrequent):

        • smooth / lamellated / sunburst pattern of periosteal reaction (cortical penetration by sheets of leukemic cells into subperiosteum) in 12 25%

        • P.113


      • Metaphyseal osteosclerosis + focal osteoblastic lesion (very rare)

        • osteosclerotic lesions (late in disease due to reactive osteoblastic proliferation)

        • mixed lesions (lytic + bone-forming) in 18%

        Dx: sternal marrow / peripheral blood smear
        Cx: proliferation of leukemic cells in marrow leads to extraskeletal hematopoiesis
        DDx: metastatic neuroblastoma, Langerhans cell histiocytosis

  • B. ADULTHOOD

    • Death usually occurs before skeletal abnormalities manifest

    • osteoporosis

    • solitary radiolucent foci (vertebral collapse)

    • permeating radiolucent mottling (proximal humerus)

    • MR:

      • diffuse decrease in signal intensity compared with normal marrow on T1WI

      • isointense / mildly hyperintense compared with normal marrow on T2WI (due to high water content of leukemic cells + displacement of fat)

      • abnormally hyperintense relative to normal marrow on STIR

Lipoblastoma

  • = rare benign postnatal proliferation of mesenchymal cells with a spectrum of differentiation ranging from prelipoblasts (spindle cells) to mature adipocytes

    Types: (a) lipoblastoma = circumscribed encapsulated form (2/3)
    (b) lipoblastomatosis = diffuse infiltrative form (1/3)
    Incidence: 30% of adipose-derived tumors in children
    Path: encapsulated immature adipose tissue (embryonal fat) separated by septa into multiple lobules
    Histo: uni- and multivacuolated lipoblasts interspersed between spindle / stellate mesenchymal cells; suspended in myxoid stroma
    Age: <3 years of age (in >90%); M:F = 2:1
    Location: subcutaneous tissue of extremities, neck, trunk, perineum, retroperitoneum
    Size: 3 5 cm

  • gradually increasing painless soft-tissue mass

  • CT:

    • tumor of fat density separated by fibrous septa

    • intratumoral fat stranding

    • NO enhancement

  • MR:

    • high signal intensity on T1WI + T2WI

    • heterogeneous texture ascribed to excessive amount of immature fat + myxoid tissue, intratumoral infarction, extensive mucoid, cystic degeneration

    • areas of increased intensity after fat suppression (DDx to lipoma)

Rx: complete excision with tendency to recur in 10 25%
DDx: liposarcoma (extremely rare in children), dermoid cyst

Lipoma of Bone

  • = INTRAOSSEOUS LIPOMA

    Incidence: <1:1,000 primary bone tumors
    Age: any (4th 6th decade); M:F = 1:1
    May be associated with: hyperlipoproteinemia

  • asymptomatic / localized bone pain

    Location: calcaneus, extremities (proximal femur > tibia, fibula, humerus), ilium, skull, mandible, maxilla, ribs, vertebrae, sacrum, coccyx, radius
    Site: metaphysis

  • expansile nonaggressive radiolucent lesion

  • loculated / septated appearance (trabeculae)

  • thin well-defined sclerotic border

  • thinned cortex (NO cortical destruction)

  • NO periosteal reaction

  • may contain clump of calcification centrally (= dystrophic calcification from fat necrosis)

    • VIRTUALLY DIAGNOSTIC:

    • @ Calcaneus

      • in triangular region between major trabecular groups (LAT projection)

      • calcified / ossified nidus

    • @ Proximal femur

      • on / above intertrochanteric line

      • marked ossification of margins of lesion

  • Radiographic appearance similar to unicameral bone cyst (infarcted lipoma = unicameral bone cyst?)

DDx: fibrous dysplasia, simple bone cyst, posttraumatic cyst, giant cell tumor, desmoplastic fibroma, chondromyxoid fibroma, osteoblastoma

Lipoma of Soft Tissue

Most common mesenchymal tumor composed of mature adipose tissue

Histo: mature fat cells (adipocytes) that are uniform in size + shape, occasionally have fibrous connective tissue as septations; fat unavailable for systemic metabolism

  • stable size after initial period of discernible growth

    Age: 5th 6th decade; M > F

    Location:

    • superficial = subcutaneous lipoma (more common) in posterior trunk, neck, proximal extremities

    • deep lipoma in retroperitoneum, mediastinum, chest wall, deep soft tissue of hands + feet; multiple in 5 7% (up to several hundred tumors)

  • mass of fat opacity / density / intensity identical to subcutaneous fat

  • cortical thickening (with adjacent parosteal lipoma)

  • CT:

    • well-defined + homogeneous tumor with low attenuation coefficient ( 65 to 120 HU)

    • no enhancement following IV contrast material

  • MR:

    • well-defined + homogeneous, often with septations

    • signal intensity characteristics similar to subcutaneous fat: hyperintense on T1WI + moderately intense on T2WI

    • thin septations of low signal intensity (not uncommon) correspond to fibrous connective tissue

    • differentiation from other lesions by fat suppression technique

Angiolipoma

  • = lesion composed of fat separated by small branching vessels

    P.114


    Age: 2nd + 3rd decade; 5% familial incidence

  • tender

    Location: upper extremity, trunk

  • signal characteristics of fat + mixed with varying numbers of large / small vessels

  • mostly encapsulated lesion, may infiltrate

Benign Mesenchymoma

  • = long-standing lipoma with chondroid + osseous metaplasia

Infiltrating Lipoma

  • = INTRAMUSCULAR LIPOMA

  • = relatively common benign lipomatous tumor extending between muscle fibers that become variably atrophic

Peak age: 5th 6th decade; M > F
Location: thigh (50%), shoulder, upper arm

Lipoma Arborescens

  • = DIFFUSE SYNOVIAL LIPOMA

  • = lipoma-like lesion composed of hypertrophic synovial villi distended with fat, probably reactive process to chronic synovitis

Location: knee; monoarticular
Frequently associated with: degenerative joint disease, chronic rheumatoid arthritis, prior trauma

Neural Fibrolipoma

  • = FIBROLIPOMATOUS HAMARTOMA OF NERVE

  • = rare tumorlike condition characterized by sausage-shaped / fusiform enlargement of a nerve by fibrofatty tissue

    Age: early adulthood before age 30 years / at birth
    Histo: infiltration of epineurium + perineurium by fibrofatty tissue with separation of nerve bundles

  • soft slowly enlarging mass

  • pain, tenderness, decreased sensation, paresthesia

    Location: volar aspect of hand, wrist, forearm
    Site: median n. (most frequently), ulnar n., radial n., brachial plexus;
    May be associated with: macrodactyly (in 2/3) = macrodystrophia lipomatosa

  • may not be visible radiographically

  • MR:

    • longitudinally oriented, cylindrical, linear / serpiginous structures of signal void about 3 mm in diameter (= nerve fascicles with epi- and perineural fibrosis) separated by areas of fat signal intensity (= mature fat infiltrating the interfascicular connective tissue)

  • US:

    • cablelike appearance = alternating hyper- and hypoechoic bands on US

DDx: cyst, ganglion, lipoma, traumatic neuroma, plexiform neurofibroma, vascular malformation

Liposarcoma

  • Malignant tumor of mesenchymal origin with bulk of tumor tissue differentiating into adipose tissue

    Incidence: 12 18% of all malignant soft-tissue tumors; 2nd most common soft-tissue sarcoma in adults (after malignant fibrous histiocytoma)
    Age: 5th 6th decade

  • Histo:

    • rarely arising from lipoma

      • myxoid type (most common, in 40 50%): varying degrees of mucin + fibrous tissue + relatively little lipid (<10%) = intermediate differentiation

        • radiodensity between water + muscle

      • lipogenic type: malignant lipoblasts with large amounts of lipid + scanty myxoid matrix = well-differentiated

        • radiodensity of fat with thick + poorly defined streaks of high attenuation

      • pleomorphic type (least common): marked cellular pleomorphism, paucity of lipid + mucin

        • = highly undifferentiated

        • radiodensity of muscle (no distinguishing imaging features from other soft-tissue sarcomas)

  • usually painless mass (may be painful in 10 15%)

    Location: lower extremity (45%), abdominal cavity + retroperitoneum (14%), trunk (14%), upper extremity (7.6%), head & neck (6.5%), miscellaneous (13.5 %)
    Spread: hematogenous to lung, visceral organs; myxoid liposarcoma shows tendency for serosal + pleural surfaces, subcutaneous tissue, bone

  • nonspecific soft-tissue mass (frequently fat is radiologically not detectable)

  • inhomogeneous mass with soft-tissue + fatty components

  • enhancement after IV contrast material (contradistinction to lipoma)

  • concomitant mass in retroperitoneum / thigh (in up to 10% of myxoid liposarcomas) as multicentric lesion / metastasis

  • mass of near water density / hypoechoic / hypointense on T1WI + hyperintense on T2WI in myxoid liposarcoma (high content of myxoid cells)

Lyme Arthritis

Agent: spirochete Borrelia burgdorferi; transmitted by tick Ixodes dammini
Histo: inflammatory synovial fluid, hypertrophic synovia with vascular proliferation + cellular infiltration

  • history of erythema chronicum migrans

  • endemic areas: Lyme, Connecticut, first recognized location; now also throughout United States, Europe, Australia

  • recurrent attacks of arthralgias within days to 2 years after tick bite (80%)

    Location: mono- / oligoarthritis of large joints (especially knee)

  • erosion of cartilage / bone (4%)

    Rx: antibiotics
    DDx: (1) Rheumatic fever
    (2) Rheumatoid arthritis
    (3) Gonococcal arthritis
    (4) Reiter syndrome

Lymphangioma

  • = sequestered noncommunicating lymphoid tissue lined by lymphatic endothelium

    Cause: congenital obstruction of lymphatic drainage

    Subtypes:

    • Capillary lymphangioma (rare)

      Location: subcutaneous tissue

      • P.115


    • Cavernous lymphangioma

      Location: about the mouth + tongue

    • Cystic lymphangioma (most common)

      • = cystic hygroma

        Associated with: hydrops fetalis, Turner syndrome
        Location: head, neck (75%), axilla (20%), extension into mediastinum (3 10%)

      • soft fluctuant mass

      • Lymphangiomas are frequently a mixture of subtypes!

Age: found at birth (50 65%); within first 2 years of life (90%)
Location: soft tissue; bone (rare)

  • multilocular cystic lesion with fibrous septations

  • occasionally serpentine vascular channels

  • opacification during lymphangiography / direct puncture

  • clear / milky fluid on aspiration

    DDx: hemangioma (blood on aspiration)

Lymphangiomatosis of bone

  • = MASSIVE OSTEOLYSIS = GORHAM-Stout DISEASE = VANISHING BONE DISEASE = PHANTOM BONE Disease

  • = infrequent disorder of bone + soft tissues secondary to persistence of dilated lymphatics from 14 20th week EGA

    Incidence: >100 cases described
    Histo: massive proliferation of hemangiomatous / lymphangiomatous tissue with large sinusoid spaces + fibrosis
    Age: infants + children, M=F
    Associated with: cystic hygroma (neck, axilla, chest wall, mediastinum), splenic cysts, chylothorax, soft-tissue hemangiomas without calcifications

  • frequently history of severe trauma (50%)

  • little / no pain

    Location: any bone (frequently multiple locations); most commonly major long bones (humerus, shoulder, mandible), pelvis, spine, thorax, short tubular bones of hand + feet (unusual)

  • progressive relentless resorption / destruction of bone:

    • patchy osteopenia (early)

    • expanding intramedullary lesion (later)

    • complete resorption of entire bone segments (late)

  • lack of reaction (no periosteal reaction, minimal sclerosis)

  • advancing edge of destruction not sharply delineated

  • tapering margins of bone ends at sites of osteolysis with conelike spicule of bone (early changes)

  • no respect for joints

    DDx: Langerhans cell histiocytosis, fibrous dysplasia, brown tumor of hyperparathyroidism

Lymphoma of Bone

  • = RETICULUM CELL SARCOMA = HISTIOCYTIC LYMPHOMA = PRIMARY LYMPHOMA OF BONE

  • = singular bone lesion

  • the generalized form of reticulum cell sarcoma is lymphoma

    Prevalence: 5% of all primary bone tumors; <1% of all NHL; 2 6% of all primary malignant bone tumors in children

  • Incidence of bone marrow involvement:

    • 5 15% in Hodgkin disease;

    • 25 40% in non-Hodgkin lymphoma

    • Bone marrow involvement indicates progression of disease

    • Bone marrow imaging-guidance for biopsy!

      NUC: 40% sensitivity; 88% specificity
      MR: 65% sensitivity; 90% specificity
    Histo: mostly large B-cell category; sheets of reticulum cells, larger than those in Ewing sarcoma (DDx: myeloma, inflammation, osteosarcoma, eosinophilic granuloma)
    Age: bimodal distribution with peaks in 2nd 3rd and 5th 6th decades; 50% <40 years; 35% <30 years; M:F = 2:1

  • chronic dull pain

  • striking contrast between size of lesion + patient's well-being

    Location: lower femur, upper tibia (40% about knee), humerus, pelvis, scapula, ribs, vertebra
    Site: dia- / metaphysis

  • cancellous bone erosion (earliest sign)

  • mottled permeative pattern of separate coalescent areas

  • late cortical destruction

  • lamellated / sunburst periosteal response (rare and less than in Ewing sarcoma)

  • lytic / reactive new-bone formation

  • associated soft-tissue mass without calcification (70%)

  • synovitis of knee joint common

    Cx: pathologic fracture (most common among malignant bone tumors)
    Prognosis: 54% 5-year survival
    DDx: (1) Osteosarcoma (less medullary extension, younger patients)
    (2) Ewing tumor (systemic symptoms, debility, younger patients)
    (3) Metastatic malignancy (multiple bones involved, more destructive)

Macrodystrophia Lipomatosa

  • = rare nonhereditary congenital form of localized gigantism = neural fibrolipoma with macrodactyly

    Path: striking increase in adipose tissue in a fine fibrous network involving periosteum, bone marrow, nerve sheath, muscle, subcutaneous tissue
    May be associated with: syn-, clino-, polydactyly

  • painless

    Location: 2nd or 3rd digit of hand / foot; unilateral; one / few adjacent digits may be involved in the distribution of the median / plantar nerves

  • long + broad splayed phalanges with endosteal + periosteal bone deposition

  • overgrowth of soft tissue, greatest at volar + distal aspects

  • slanting of articular surfaces

  • lucent areas of fat (DIAGNOSTIC)

    Prognosis: accelerated maturation possible; growth stops at puberty
    DDx: fibrolipomatous hamartoma associated with macrodystrophia lipomatosa (indistinguishable), Klippel-Trenaunay-Weber syndrome, lymphangiomatosis, hemangiomatosis, neurofibromatosis, chronic vascular stimulation, Proteus syndrome

Marfan Syndrome

  • = ARACHNODACTYLY

  • = autosomal dominant familial disorder of connective tissue with high penetrance but extremely variable expression, new mutations in 15%

    P.116


    Etiology: fibrillin gene defect on chromosome 15 resulting in abnormal cross-linking of collagen fibers
    Prevalence: 5:100,000; M:F = 1:1

  • A. MUSCULOSKELETAL MANIFESTATIONS

    • tall thin stature with long limbs, arm span greater than height

    • muscular hypoplasia + hypotonicity

    • scarcity of subcutaneous fat (emaciated look)

    • generalized osteopenia

    • @ Skull

      • elongated face

      • dolichocephaly

      • prominent jaw

      • high arched palate

    • @ Hand

      • Steinberg sign = protrusion of thumb beyond the confines of the clenched fist (found in 1.1% of normal population)

      • metacarpal index (averaging the 4 ratios of length of 2nd through 5th metacarpals divided by their respective middiaphyseal width) >8.8 (male) or 9.4 (female)

      • arachnodactyly = elongation of phalanges + metacarpals

      • flexion deformity of 5th finger

    • @ Foot

      • pes planus

      • clubfoot

      • hallux valgus

      • hammer toes

      • disproportionate elongation of 1st digit of foot

    • @ Spine

      • ratio of measurement between symphysis and floor + crown and floor >0.45

      • pectus carinatum / excavatum (common)

      • scoliosis / kyphoscoliosis (45 60%)

      • increased incidence of Scheuermann disease and spondylosis

      • dural ectasia

      • increased interpedicular distance

      • posterior scalloping

      • presacral + lateral sacral meningoceles

      • expansion of sacral spinal canal

      • enlargement of sacral foramina

      • winged scapulae

    • @ Joints

      • ligamentous laxity + hypermobility + instability

      • premature osteoarthritis

      • patella alta

      • genu recurvatum

      • recurrent dislocations of patella, hip, clavicle, mandible

      • slipped capital femoral epiphysis

      • progressive protrusio acetabuli (50%), bilateral > unilateral, F > M

  • B. OCULAR MANIFESTATIONS

    • bilateral ectopia lentis, usually upward + outward (secondary to poor zonular attachments)

    • glaucoma, macrophthalmia

    • hypoplasia of iris + ciliary body

    • contracted pupils (absence of dilator muscle)

    • myopia, retinal detachment

    • strabismus, ptosis

    • blue sclera

    • megalocornea = flat enlarged thickened cornea

  • C. CARDIOVASCULAR MANIFESTATIONS (60 98%)

    • affecting mitral valve, ascending aorta, pulmonary artery, splenic + mesenteric arteries (occasionally)

    • Cause of death in 93%!

    • chest pain, palpitations, shortness of breath, fatigue

    • mid-to-late systolic murmur + one / more clicks

      Associated with: congenital heart defect (33%) incomplete coarctation, ASD

    • @ Aorta (cause of death in 55%)

      Histo: myxomatous degeneration of aortic annulus

      • tulip bulb aorta = symmetrical dilatation of aortic sinuses of Valsalva slightly extending into ascending aorta (58%)

      • annuloaortic ectasia = combination of aortic root dilatation + aortic regurgitation

      • fusiform aneurysm of ascending aorta, rarely beyond innominate artery (due to cystic medial necrosis)

      • aortic wall calcification rare

        Cx: (1) Aortic regurgitation (in 81% if root diameter >5 cm; in 100% if root diameter >6 cm
        (2) Aortic dissection
        (3) Aortic rupture (secondary to progressive aortic root dilatation)

    • @ Mitral valve

      Histo: myxomatous degeneration of valve leads to redundancy + laxness

      • mid-to-late systolic murmur + one / more clicks

      • floppy valve syndrome (95%) = redundant chordae tendineae with mitral valve prolapse + regurgitation

        Cx: (1) Mitral regurgitation
        (2) Rupture of chordae tendineae (rare)

    • @ Coarctation (mostly not severe)

    • @ Pulmonary artery aneurysm + dilatation of pulmonary arterial root (43%)

    • @ Cor pulmonale (secondary to chest deformity)

  • D. PULMONARY MANIFESTATIONS

    • cystic lung disease

    • recurrent spontaneous pneumothoraces

  • E. ABDOMINAL MANIFESTATION

    • recurrent biliary obstruction

      DDx: (1) Homocystinuria (osteoporosis)
      (2) Ehlers-Danlos syndrome
      (3) Congenital contractural arachnodactyly (ear deformities, NO ocular / cardiac abnormalities)
      (4) Type III MEN (medullary thyroid carcinoma, mucosal neuromas, pheochromocytoma, marfanoid habitus)

Melorheostosis

  • Nonhereditary disease of unknown etiology; often incidental finding

    P.117


    Age: slow chronic course in adults; rapid progression in children
    Associated with: osteopoikilosis, osteopathia striata, tumors / malformations of blood vessels (hemangioma, vascular nevi, glomus tumor, AVM, aneurysm, lymphedema, lymphangiectasia)

  • severe pain + limited joint motion (bone may encroach on nerves, blood vessels, or joints)

  • thickening + fibrosis of overlying skin (resembling scleroderma)

  • muscle atrophy (frequent)

    Location: diaphysis, usually monomelic with at least two bones involved in dermatomal distribution (follows spinal sensory nerve sclerotomes); entire cortex / limited to one side of cortex; more common in lower limb; skull, spine, ribs rarely involved

  • candle wax dripping = continuous / interrupted streaks / blotches of sclerosis along tubular bone beginning at proximal end extending distally with slow progression

  • may cross joint with joint fusion

  • small opacities in scapula + hemipelvis (similar to osteopoikilosis)

  • discrepant limb length

  • flexion contractures of hip + knee

  • genu valgum / varus

  • dislocated patella

  • ossified soft-tissue masses (27%)

    DDx: (1) Osteopoikilosis (generalized)
    (2) Fibrous dysplasia (normal bone structure not lost, not as dense)
    (3) Engelmann disease
    (4) Hyperostosis of neurofibromatosis, tuberous sclerosis, hemangiomas
    (5) Osteoarthropathy

Orientation of Meniscal Tears

Meniscal Tear

Cause: acute injury, degeneration related to aging

Type of cross-sectional tear pattern:

  • vertical tear with longitudinal / radial / oblique surface pattern

  • horizontal tear with longitudinal / oblique / cleavage surface pattern

  • mixed pattern

Type of arthroscopic surface pattern:

  • LONGITUDINAL TEAR

    • = tear oriented parallel to outer margin of meniscus

    • (a) vertical tear

      • full-thickness tear = extension to inferior + superior surfaces

      • partial-thickness tear = extension only to one surface

        Rx: may be amenable to repair if
        (a) in vascularized outer 3 5 mm
        (b) between 7 and 40 mm long
        (c) no degenerative changes

      • 1. Single peripheral longitudinal vertical tear

        Cause: traumatic

        • vertical tear in peripheral third of meniscus

      • 2. Bucket handle tear

        • = longitudinal vertical tear with unstable displaced inner fragment (= handle of bucket)

          Cause: traumatic
          Age: frequently in young individuals
          Frequency: 9 19% of symptomatic patients; 10% of all meniscal tears
          Associated with: ACL injury in up to 40%

        • locked knee, lack of full knee extension

          Site: medial: lateral meniscus = 2 3:1

        • absent bow-tie sign (sagittal image) = peripheral image fails to demonstrate normal bow-tie configuration on >2 consecutive images (71 98% sensitive, 63% specific)

        • hypoplastic / truncated anterior + posterior horns on sagittal image

        • double PCL sign (sagittal image) = meniscal fragment displaced into notch between PCL and medial tibial eminence oriented parallel to PCL (>98% specific, 27 44% sensitive, 93% PPV)

        • fragment-in-notch sign (coronal image) = displaced fragment in intercondylar notch

        • flipped meniscus sign

          Rx: arthroscopic / surgical repair

      • 3. Broken bucket-handle tear

      • 4. Double / triple vertical longitudinal bucket-handle tear

    • (b) horizontal tear (Cleavage Tear)

      • = divides meniscus in superior + inferior fragments

        Cause: usually degenerative
        Associated with: meniscal cyst
        Site: primarily involving the central horizontal plane of meniscus beginning at inner margin
        Rx: partial meniscectomy

  • RADIAL TEAR = TRANSVERSE TEAR (6%)

    • = vertical tear perpendicular to free edge of meniscus; may extend partially / completely through the meniscus to its outer circumference

      • P.118


    • tears <3 mm may be asymptomatic

      Site: posterior + mid third of lateral meniscus

    • usually seen on only 1 image

    • blunting of the inner margin of meniscus (if image plane parallel to tear)

    • poorly defined meniscus with diffusely increased signal intensity (if tear extends to outer margin)

    • normal meniscus in adjacent sections

    • discrete vertical focus of increased signal intensity (if image plane perpendicular to tear)

      Cx: lack of resistance to hoop stresses
      Rx: partial resection often necessary

    • 1. Parrot beak tear

      • = free edge tear with vertical + horizontal component

        Cause: usually degenerative
        Site: in body of lateral meniscus near the junction of body + posterior horn

      • fraying of free edge

    • 2. Root tear

      • = tear in anterior / posterior horn

  • OBLIQUE / FLAP TEAR

    • = composite of a radial tears that curves into a longitudinal tear

      Cause: traumatic, at times degenerative
      Frequency: most common type of tear
      Site: common in midportion of medial meniscus

    • both horizontal and vertical components

    • commonly extending to inferior surface of meniscus

      Rx: partial meniscectomy

      Distinctive Meniscal Tear Patterns

      MR Classification of Meniscal Injury

      Grade Type MR Finding PPV for Tear
      0 0 normal meniscus 1%
      1 I globular / punctate intrameniscal signal 2%
      2 II linear signal not extending to surface 5%
        III short tapered apex of meniscus 23%
        IV truncated / blunted apex of meniscus 71%
      3 V signal extending to only one surface 85%
      3 VI signal extending to both surfaces 95%
      3 VII comminuted reticulated signal pattern 82%

  • MENISCOCAPSULAR SEPARATION

    • = Peripheral Tear

    • = tearing of peripheral attachments of meniscus

    • linear region of fluid separating meniscus from capsule

    • uncovering of a portion of tibial plateau owing to inward movement of separated meniscus

Site of injury:

  • medial meniscus in 45%: no isolated tears of body / anterior horn

  • lateral meniscus in 22%: posterior horn involved in 80% of all lateral meniscal tears

  • both menisci involved in 33%

Associated with: ligamentous injury

  • asymptomatic in up to 20% of older individuals

  • MR:

    • direct signs:

      • signal extending to articular surface:

        • 2 images with signals contacting the surface (95% PPV)

        • 1 image with signal to surface (33% PPV)

        • Diagnosis of tear hinges on surface involvement!

        • Intrameniscal signal may be a sign of

          • myxoid degeneration

          • normal collagen bundles

          • persistent vascularity in children + young adults

          • contusion

        • Truncation artifact + magic angle artifact may cause increased intrameniscal signal!

      • distortion of meniscal shape

    • indirect signs

      • parameniscal cyst (meniscal tear in 98 100%)

      • posterior lip medial tibial plateau bone bruise (64% PPV for meniscal tear mostly in periphery)

      • torn popliteomeniscal fascicle (79% PPV)

  • MR sensitivity, specificity, and accuracy:

    Tear of Sensitivity Specificity Accuracy
    Medial meniscus 95% 88% 59 92%
    Lateral meniscus 81% 96% 87 92%
    Anterior cruciate lig.     91 96%
    Posterior cruciate lig.     up to 99%

    • MR has a high negative predictive value!

    • 60 97% accuracy for arthrography

    • 84 99% accuracy for arthroscopy (poor at posterior horn of medial meniscus)

  • Interpretative errors (12% for experienced radiologist):

    Lateral meniscus: 5.0% FN (middle + posterior horn)
    1.5% FP (posterior horn)
    Medial meniscus: 2.5% FN (posterior horn)
    2.5% FP (posterior horn)

PITFALLS:

  • Normal variants simulating tears:

    • Superior recess on posterior horn of medial meniscus

    • Popliteal hiatus

      • hiatus of popliteal tendon separates lateral meniscus from joint capsule

      • Seen above posterior aspect of lateral meniscus on most superficial sagittal slice!

        • P.119


      • Tendon moves behind + inferior to meniscus on adjacent deeper sections!

    • Transverse ligament

      Course: connects anterior horns of both menisci

      • overrides superior aspect of menisci before completely fusing to menisci

      • Trace the cross section of the transverse ligament through the infrapatellar fat pad on more central images!

    • Meniscofemoral ligaments

      Origin: superior + medial aspect of posterior horn of lateral meniscus
      Attachment: medial femoral condyle

      • demonstrated in 1/3 of cases on SAG images

      • (a) Wrisberg ligament

        • posterior to posterior cruciate ligament

      • (b) Humphrey ligament

        • anterior to posterior cruciate ligament

        • Finding usually limited to single most medial image!

    • Soft tissue between capsule + medial meniscus

  • Healed meniscus

    • persistent grade 3 signal at least up to 6 months

    • S/P meniscectomy (false-positive type IV finding)

  • Degenerative changes

    • grade 1 signal = globular increase in intensity

    • grade 2 signal = linear signal not extending to articular surface

  • Diskoid meniscus

    • = abnormally shaped enlarged diskus-like meniscus

      Prevalence: in 1.5 3% for lateral meniscus; 0.12 0.3% for medial meniscus
      Age: children, adolescents
      Side: lateral: medial meniscus = 10:1

    • >2 bowtie slices on sagittal image

    • >15 mm width on coronal image

    • centrally displaced fragment with meniscus apparently of normal size (coronal images)

Mesomelic Dwarfism

  • = heritable bone dysplasia with shortening of intermediate segments (radius + ulna or tibia + fibula)

  • A. Langer type autosomal recessive

    • mental impairment

    • mesomelic shortening of limbs

    • hypoplasia of ulna + fibula

    • hypoplasia of mandible with short condyles

  • B. Nievergelt type autosomal dominant

    • severe mesomelic shortening of lower limbs

    • marked thickening of tibia + fibula in central portion

    • clubfoot (frequent)

  • C. Reinhardt type: autosomal dominant

  • D. Robinow type: autosomal dominant

  • E. Werner type: autosomal dominant

  • F. Lamy-Bienenfeld type autosomal dominant

    • ligamentous laxity

    • shortening of radius + ulna + tibia

    • absent fibula

    • normal femur + humerus

    • shortening of all long bones at birth, most marked in tibia + radius

    • modeling deformity with widening of diaphysis

    • mild to moderate bowing

    • hypoplasia of fibula with absent lateral malleolus

    • short + thick ulna with hypoplastic distal end

    • Madelung deformity of wrist

    • hypoplasia of a vertebral body may be present

Metaphyseal Chondrodysplasia

  • = severe short-limbed dwarfism

  • metaphyseal flaring (Erlenmeyer flask deformity) extending into diaphysis

  • A. Schmid type (most common)

    • autosomal dominant

    • waddling gate

      Distribution: more marked in lower limbs; mild involvement of hands + wrists

    • shortened bowed long bones

    • widened epiphyseal growth plates

    • irregular widened cupped metaphyses

    • coxa vara

    • genu varum

      DDx: vitamin D refractory rickets

  • B. McKusick type

    • autosomal recessive (eg, in Amish)

    • sparse brittle hair, deficient pigmentation

    • normal intelligence

    • shortening of long bones with normal width

    • cupped + widened metaphyses with lucent defects

    • short middle phalanges + narrow distal phalanges becoming triangular and bullet-shaped (more frequent in hands than feet)

    • widened costochondral junctions + cystic lucencies

  • C. Jansen type (less common)

    • sporadic occurrence with wide spectrum

    • intelligence normal / retarded

    • serum calcium levels often elevated

      Distribution: symmetrical involvement of all long + short tubular bones

    • widened epiphyseal plates

    • expanded irregular + fragmented metaphyses (unossified cartilage extending into diaphyses)

      DDx: rickets

  • D. Pyle disease = Metaphyseal dysplasia

    • often tall

    • often asymptomatic

      Distribution: major long bones, tubular bones of hands, medial end of clavicle, sternal end of ribs, innominate bone

    • splaying of proximal + distal ends of long bones with thinned cortex

    • relative constriction of central portion of shafts

    • craniofacial hyperostosis

    • genu valgum

Metastases to Bone

  • 15 100 times more common than primary skeletal neoplasms!

P.120


Frequency:

If primary known If primary unknown
Breast 35% Prostate 25%
Prostate 30% Lymphoma 15%
Lung 10% Breast 10%
Kidney 5% Lung 10%
Uterus 2% Thyroid 2%
Stomach 2% Colon 1%
Others 13%    

SOLITARY BONE LESION

  • Of all causes only 7% are due to metastasis

  • In patients with known malignancy solitary bone lesions are due to metastasis (55%), due to trauma (25%), due to infection (10%)

Location: axial skeleton (64 68%), ribs (45%), extremities (24%), skull (12%)
mnemonic: Several Kinds Of Horribly Nasty Tumors Leap Promptly To Bone

  • Sarcoma, Squamous cell carcinoma

  • Kidney tumor

  • Ovarian cancer

  • Hodgkin disease

  • Neuroblastoma

  • Testicular cancer

  • Lung cancer

  • Prostate cancer

  • Thyroid cancer

  • Breast cancer

Breast cancer: extensive osteolytic lesions; involvement of entire skeleton; pathologic fractures common
Thyroid / kidney: often solitary; rapid progression with bone expansion (bubbly); frequently associated with soft-tissue mass (distinctive)
Rectum / colon: may resemble osteosarcoma with sunburst pattern + osteoblastic reaction
Hodgkin tumor: upper lumbar + lower thoracic spine, pelvis, ribs; osteolytic / occasionally osteoblastic lesions
Osteosarcoma: 2% with distant metastases, adjuvant therapy has changed the natural history of the disease in that bone metastases occur in 10% of osteosarcomas without metastases to the lung
Ewing sarcoma: extensive osteolytic / osteoblastic reaction (13% with distant metastases)
Neuroblastoma: extensive destruction, resembles leukemia (metaphyseal band of rarefaction), mottled skull destruction + increased intracranial pressure, perpendicular spicules of bone
Mode of spread: through bloodstream / lymphatics / direct extension
Location: predilection for marrow-containing skeleton (skull, spine, ribs, pelvis, humeri, femora)

  • single / multiple lesions of variable size

  • usually nonexpansile

  • joint spaces + intervertebral spaces preserved (cartilage resistant to invasion)

Osteolytic Bone Metastases

Most common cause: neuroblastoma (in childhood); lung cancer (in adult male); breast cancer (in adult female), thyroid cancer; kidney; colon

  • may begin in spongy bone (associated with soft tissue mass in ribs)

  • vertebral pedicles often involved (not in multiple myeloma)

Osteoblastic Bone Metastases

  • = evidence of slow-growing neoplasm

    Primary: prostate, breast, lymphoma, malignant carcinoid, medulloblastoma, mucinous adenocarcinoma of GI tract, TCC of bladder, pancreas, neuroblastoma
    Most common cause: prostate cancer (in adult male); breast cancer (in adult female)
    mnemonic: 5 Bees Lick Pollen

    • Brain (medulloblastoma)

    • Bronchus

    • Breast

    • Bowel (especially carcinoid)

    • Bladder

    • Lymphoma

    • Prostate

  • frequent in vertebrae + pelvis

  • may be indistinguishable from Paget disease

Mixed Bone Metastases

breast, prostate, lymphoma

Expansile / Bubbly Bone Metastases

kidney, thyroid

Permeative Bone Metastases

Burkitt lymphoma, mycosis fungoides

Bone Metastases with Sunburst Periosteal Reaction

  • (infrequent)

  • prostatic carcinoma, retinoblastoma, neuroblastoma (skull), GI tract

Bone Metastases with Soft-tissue Mass

thyroid, kidney

Calcifying Bone Metastases

mnemonic: BOTTOM

  • Breast

  • Osteosarcoma

  • Testicular

  • Thyroid

  • Ovary

  • Mucinous adenocarcinoma of GI tract

Skeletal Metastases in Children

  • Neuroblastoma (most often): diffuse / focal

  • Lymphoma

  • Rhabdomyosarcoma

  • Ewing sarcoma

  • Retinoblastoma

  • Hepatoma

P.121


Skeletal Metastases in Adult

mnemonic: Common Bone Lesions Can Kill The Patient

  • Colon

  • Breast

  • Lung

  • Carcinoid

  • Kidney

  • Thyroid

  • Prostate

Role of Bone Scintigraphy in Bone Metastases

Pathophysiology: accumulation of tracer at sites of reactive bone formation
False-negative scan: very aggressive metastases
False-positive scan: degeneration, healing fractures, metabolic disorders

  • Baseline bone scan:

    • high sensitivity for many metastatic tumors to bone (particularly carcinoma of breast, lung, prostate); 5% of metastases have normal scan; 5 40% occur in appendicular skeleton

    • substantially less sensitive than radiographs in infiltrative marrow lesions (multiple myeloma, neuroblastoma, histiocytosis)

    • screening of asymptomatic patients

      • useful in: prostate cancer, breast cancer

      • not useful in: non small-cell bronchogenic carcinoma, gynecologic malignancy, head and neck cancer

    • multiple asymmetric areas of increased uptake

    • axial > appendicular skeleton (dependent on distribution of bone marrow); vertebrae, ribs, pelvis involved in 80%

    • superscan in diffuse bony metastases

  • Follow-up bone scan:

    • stable scan = suggestive of relatively good prognosis

    • increased activity in:

      • enlargement of bone lesions / appearance of new lesions indicate progression of the disease

      • healing flare phenomenon (in 20 61%) = transient increase in lesion activity secondary to healing under antineoplastic treatment concomitant with increased sclerosis, detected at 3.2 1.4 months after initiation of hormonal / chemotherapy, of no additional favorable prognostic value

      • avascular necrosis particularly in hips, knees, shoulders caused by steroid therapy

      • osteoradionecrosis / radiation-induced osteosarcoma

    • decreased activity in:

      • predominately osteolytic destruction

      • metastases under radiotherapy; as early as 2 4 months with minimum of 2000 rads

DDx: pulmonary metastasis (SPECT helpful in distinguishing nonosseous lung from overlying rib uptake)

Role of Bone Scan in Breast Cancer

  • Routine preoperative bone scan not justified:

    Stage I: unsuspected metastases in 2%, mostly single lesion
    Stage II: unsuspected metastases in 6%
    Stage III: unsuspected metastases in 14%

  • Follow-up bone scan:

    • At 12 months no new cases; at 28 months in 5% new metastases; at 30 months in 29% new metastases

    • Conversion from normal:

      Stage I: in 7%
      Stage II: in 25%
      Stage III: in 58%

    • With axillary lymph node involvement conversion rate 2.5 that of those without!

    • Serial follow-up examinations are important to assess therapeutic efficacy + prognosis!

Role of Bone Scan in Prostate Cancer

Stage B: 5% with skeletal metastases
Stage C: 10% with skeletal metastases
Stage D: 20% with skeletal metastases

  • Test sensitivities for detection of osseous metastases:

    • scintigraphy 1.0

    • radiographic survey 0.68

    • alkaline phosphatase 0.5

    • acid phosphatase 0.5

Role of Magnetic Resonance Imaging in Bone Metastases

  • ideal for bone marrow imaging due to high contrast between bone marrow fat + water-containing metastatic deposits

  • Metastases are most often found in sites of dominant hematopoietic marrow because of its rich vascular supply!

in children: proximal + distal metaphyses of long bones, flat bones, spine
in adults: calvarium, spine, flat bones, proximal humeral + femoral metaphyses

  • Focal lytic lesion (usual):

    • hypointense on T1WI (more conspicuous when surroundings contain large number of fat cells)

    • hyperintense on T2WI / STIR (due to increased water content of hypercellular tumor tissue)

    • occasionally surrounded by mild edema

  • Focal sclerotic lesion

    • (eg, medulloblastoma, retinoblastoma):

    • hypointense on T1WI + T2WI (bone production)

  • Diffuse heterogeneous lesions (eg, neuroblastoma):

    • inhomogeneously hypointense on T1WI + hyperintense on T2WI

  • Diffuse homogeneous lesions:

    • homogeneously hypointense on T1WI + hyperintense on T2WI

Metatrophic Dysplasia

  • = HYPERPLASTIC ACHONDROPLASIA = METATROPHIC DWARFISM

  • metatrophic = changeable (change in proportions of trunk to limbs over time secondary to developing kyphoscoliosis in childhood)

  • longitudinal double skin fold overlying coccyx

  • long bones short with dumbbell-like / trumpet-shaped configuration (exaggerated metaphyseal flaring)

  • hourglass phalanges (short with widened ends)

  • wide separation of major joint spaces (thick articular cartilage)

  • delayed ossification of flat irregular epiphyses

P.122


  • @ Chest

    • cylindrical narrowed elongated thorax

    • short + wide ribs

    • pectus carinatum

  • @ Vertebrae

    • odontoid hypoplasia with atlantoaxial instability

    • progressive kyphoscoliosis

    • platyspondyly + very wide intervertebral spaces

    • wedge- / keel-shaped vertebral bodies

  • @ Pelvis

    • coccygeal appendage similar to a tail (rare but CHARACTERISTIC)

    • short squared iliac bones + irregular acetabula

    • narrowed greater sciatic notch

Prognosis: compatible with life, increased disability from kyphoscoliosis
DDx: achondroplasia, mucopolysaccharidoses

Methotrexate Osteopathy

  • = syndrome that consists of

    • bone pain

    • osteopenia

    • pathologic fractures

  • Methotrexate

    • = dihydrofolate reductase inhibitor most often used in children for treatment of ALL / osteosarcoma / brain tumor

  • Radiographic findings similar to scurvy:

    • osteopenia

    • dense provisional zones of calcification

    • pathologic fractures (most often metaphyseal)

    • sharply outlined epiphyses

    • NO massive subperiosteal hemorrhage

    • impaired healing of fractures

Morton Neuroma

  • = INTERDIGITAL NEUROMA

    Age: highest prevalence in 5th + 6th decade; M:F = 1:4
    Path: perineural fibrosis entrapping a plantar digital nerve; neuroma is a misnomer
    Often associated with: intermetatarsal bursitis
    Histo: dense collagenous + fibrous tissue

  • numbness; burning / tingling electric forefoot pain increasing with activity + wearing of narrow shoes

  • Mulder sign = painful palpable click when metatarsal heads are squeezed together with one hand + involved metatarsal space simultaneously compressed between thumb and index finger of the other hand

    Location: plantar side of deep transverse intermetatarsal ligament
    Site: typically 2nd / 3rd intermetatarsal space (rarely 1st / 4th)

  • MR (87% sensitive, 100% specific):

    • small well-demarcated teardrop-shaped mass isointense to muscle on T1WI + hypointense to fat on T2WI

    • fluid in intermetatarsal bursa

    • Best depicted prone (positional changes)

    • fluid in intermetatarsal bursa (vertically oriented between metatarsal heads)

Rx: conservative treatment; surgical excision for neuromas >5 mm in transverse diameter (more commonly symptomatic)

Mucopolysaccharidoses

  • = lysosomal storage disorder from deficiency of specific lysosomal enzymes involved in degradation of mucopolysaccharides

  • Types:

    • Type I = Hurler

    • Type II = Hunter

    • Type III = Sanfilippo

    • Type IV = Morquio (most common)

    • Type V = Scheie

    • Type VI = Maroteaux-Lamy

    • Type VII = Sly

  • All autosomal recessive except for Hunter (X-linked)!

    Associated with: valvular heart disease

  • corneal clouding

  • retardation (prominent in types I, II, III, VII)

  • skeletal involvement dominates in types IV and VI

  • scaphocephaly, macrocephaly; thick calvarium; hypertelorism

  • platyspondyly with kyphosis + dwarfism

  • irregularity at anterior aspect of vertebral bodies

  • atlantoaxial subluxation + instability (laxity of transverse ligament / hypoplasia or absence of odontoid)

  • limb contractures

  • broad hands + brachydactyly

  • hepatosplenomegaly

  • @ Brain

    • brain atrophy

    • varying degree of hydrocephalus

    • multiple white matter changes within cerebral hemispheres (diffuse hypodense areas, prolongation of T1 + T2)

Cx: cord compression at atlantoaxial joint (types IV + VI)
Dx: combination of clinical features, radiographic abnormalities correlated with genetic + biochemical studies
Prenatal Dx: occasionally successful analysis of fibroblasts cultured from amniotic fluid
DDx: Gaucher disease, Niemann-Pick disease

Hurler Syndrome

  • = GARGOYLISM = PFAUNDLER-HURLER DISEASE

  • = MPS I-H

  • = autosomal recessive disease

    Cause: homozygous for MPS III gene with excess chondroitin sulfate B due to deficient X-L iduronidase (= Hurler corrective factor)
    Incidence: 1:10,000 births
    Age: usually appears >1st year

  • dwarfism

  • progressive mental deterioration after 1 3 years

  • large head; sunken bridge of nose; hypertelorism

  • early corneal clouding progressing to blindness

  • gargoyle features = everted lips + protruding tongue

  • teeth widely separated + poorly formed

  • progressive narrowing of nasopharyngeal airway

  • protuberant abdomen (secondary to dorsolumbar kyphosis + hepatosplenomegaly)

  • urinary excretion of chondroitin sulfate B (dermatan sulfate) + heparan sulfate

    P.123


    Mucopolysaccharidoses

    Type Eponym Inheritance Enzyme Deficiency Urinary Glycosaminoglycan Neurologic Signs
    I-H Hurler autosomal recessive alpha-L-iduronidase dermatan sulfate marked
    II Hunter X-linked recessive iduronate sulfatase dermatan / heparan sulfate mild to moderate
    III Sanfilippo autosomal recessive   heparan sulfate mental deterioration
      A   heparan sulfate sulfatase    
      B   N-acetyl-alpha-D-glucosaminidase    
      C   alpha-glucosamine-N-acetyl-transferase    
      D   N-acetylglucosamine-6-sulfate sulfatase    
    IV Morquio autosomal recessive N-acetylgalactosamine-6-sulfate sulfatase keratan sulfate none
      A D   beta-galactosidase    
    I-S(V) Scheie autosomal recessive alpha-L-iduronidase heparan sulfate none
    VI Maroteaux-Lamy autosomal recessive arylsulfatase B dermatan sulfate none
    VII Sly autosomal recessive beta-glucuronidase dermatan / heparan sulfate variable

  • Reilly bodies (metachromic granules) in white blood cells or bone marrow cells

  • @ Skull (earliest changes >6 months of age)

    • frontal bossing

    • calvarial thickening

    • premature fusion of sagittal + lambdoid sutures

    • deepening of optic chiasm

    • enlarged J-shaped sella (undermining of anterior clinoid process)

    • small facial bones

    • wide mandibular angle + underdevelopment of condyles

    • communicating hydrocephalus

  • @ Extremities

    • thick periosteal cloaking of long-bone diaphyses (early changes)

    • swelling / enlargement of diaphyses + cortical thinning (due to dilatation of medullary canal) + tapering of either end: distal humerus, radius, ulna, proximal ends of metacarpals

    • deossification with heterogeneous bone density + course trabeculation (due to deposition of accumulated precursor metabolites in bone marrow)

    • flexion deformities of knees + hips

    • trident hands; clawing (occasionally)

    • delayed maturation of irregular carpal bones

  • @ Spine

    • thoracolumbar kyphosis with lumbar gibbus

    • oval centra with normal / increased height + anterior beak at T12/L1/L2

    • long slender pedicles

    • proximally long slender ribs at level of neck + wide distally = spatulate rib configuration

  • @ Pelvis

    • widely flared iliac wings with inferior tapering

    • constriction of iliac bones

    • coxa valga

Prognosis: death by age 10 15 years

Morquio Syndrome

  • = KERATOSULFATURIA = MPS IV (most common type)

  • = autosomal recessive; excess keratosulfate

Incidence: 1:40,000 births
Etiology: N-acetyl-galactosamine-6-sulfatase deficiency resulting in defective degradation of keratin sulfate (mainly in cartilage, nucleus pulposus, cornea)
Age: normal at birth; skeletal changes manifest within first 18 months; M:F = 1:1

  • excessive urinary excretion of keratan sulfate

  • normal intelligence

  • muscular weakness + hypotonia

  • ligamentous laxity, but joint stiffness

  • short-trunk dwarfism (<4 feet tall)

  • head thrust forward + sunken between high shoulders

  • corneal clouding evident around age 10

  • progressive deafness

  • coarse face with short nose, broad mouth, widely spaced teeth with thin enamel

  • semicrouching stance + knock knees from flexion deformities of knees + hips

  • @ Skull

    • mild dolichocephaly

    • hypertelorism

    • poor mastoid air cell development

      • P.124


    • short nose + depression of bridge of nose

    • prominent maxilla

  • @ Chest

    • increased AP diameter + marked pectus carinatum (horizontal protuberant sternum)

    • slight lordosis with wide short ribs

    • bulbous costochondral junctions

    • failure of fusion of sternal segments

  • @ Spine

    • hypoplasia / absence of odontoid process of C2

    • C1-C2 instability with anterior (life-threatening) atlantoaxial subluxation + progressive disabling myelopathy

    • thick C2-body with narrowing of vertebral canal

    • atlas close to occiput / posterior arch of C1 within foramen magnum

    • platyspondyly = universal vertebra plana esp. affecting lumbar spine by age 2 3 years (DDx: normal height in Hurler syndrome)

    • ovoid vertebral bodies with central anterior beak / tongue at lower thoracic / upper lumbar vertebrae

    • mild gibbus at thoracolumbar transition = low dorsal kyphosis

    • exaggerated lumbar lordosis

    • widened intervertebral disk spaces

  • @ Pelvis

    • goblet-shaped / wineglass pelvis = constricted iliac bodies + elongated pelvic inlet + broad flat flared iliac wings

    • oblique hypoplastic acetabular roofs

  • @ Femur

    • initially well-formed femoral head epiphysis, then involution + fragmentation by age 3 6 years

    • lateral subluxation of femoral heads; later hip dislocation

    • wide femoral neck + coxa valga deformity

  • @ Tibia

    • delayed ossification of lateral proximal tibial epiphysis

    • sloping of superior margin of tibia plateau laterally + severe genu valgum

  • @ Hand & foot

    • short bones of forearm with widening of proximal ends

    • delayed appearance + irregularity of carpal centers

    • small irregular carpal bones

    • proximally pointed short metacarpals 2 5

    • enlarged joints; hand + foot deformities (flat feet)

    • ulnar deviation of hand

Cx: cervical myelopathy (traumatic quadriplegia / leg pains / subtle neurologic abnormality) most common cause of death secondary to C2 abnormality; frequent respiratory infections (from respiratory paralysis)
Rx: early fusion of C1 C2
Prognosis: may live to adulthood (3rd 4th decade)
DDx: (1) Hurler syndrome (normal / increased vertebral height; vertebral beak inferior)
  (2) Spondyloepiphyseal dysplasia (autosomal dominant, present at birth, absent flared ilia / deficient acetabular ossification, small acetabular angle, deficient ossification of pubic bones, varus deformity of femoral neck, minimal involvement of hand + foot, myopia)

Multiple Epiphyseal Dysplasia

  • = FAIRBANK DISEASE

  • =? tarda form of chondrodystrophia calcificans congenita

  • mild limb shortening

  • irregular mottled calcifications of epiphyses (in childhood + adolescence)

  • epiphyseal irregularities + premature degenerative joint disease, especially of hips (in adulthood)

  • short phalanges

DDx: Legg-Perthes disease, hypothyroidism

Multiple Myeloma

  • = malignancy characterized by monoclonal proliferation of malignant plasma cells

  • Most common primary malignant neoplasm in adults!

    Histo: normal / pleomorphic plasma cells (not pathognomonic), may be mistaken for lymphocytes (lymphosarcoma, reticulum cell sarcoma, Ewing tumor, neuroblastoma)
      (a) diffuse infiltration: myeloma cells intimately admixed with hematopoietic cells
      (b) tumor nodules: displacement of hematopoietic cells by masses entirely composed of myeloma cells
    Age: usually 5th 8th decade; 98% >40 years;
      rare <30 years of age; M:F = 2:1
      (a) DISSEMINATED FORM: >40 years of age (98%); M:F = 3:2
    (b) SOLITARY FORM: mean age 50 years

  • bone pain (68%)

  • normochromic normocytic anemia (62%)

  • RBC rouleau formation

  • renal insufficiency (55%)

  • hypercalcemia (30 50%)

  • proteinuria (88%)

  • Bence Jones proteinuria (50%)

  • increased globulin production (monoclonal gammopathy)

  • Location:

    • DISSEMINATED FORM:

      • scattered; axial skeleton predominant site; vertebrae (50%) > ribs > skull > pelvis > long bones (distribution correlates with normal sites of red marrow)

    • SOLITARY PLASMACYTOMA OF BONE:

      • vertebrae > pelvis > skull > sternum > ribs

    • SPINAL PLASMA CELL MYELOMA

      • sparing of posterior elements (no red marrow) (DDx: metastatic disease)

      • paraspinal soft-tissue mass with extradural extension

      • scalloping of anterior margin of vertebral bodies (osseous pressure from adjacent enlarged lymph nodes)

  • generalized osteopenia only (15%) with accentuation of trabecular pattern, especially in spine (early)

  • punched out appearance of widespread osteolytic lesions (skull, long bones) with endosteal scalloping and of uniform size

  • diffuse osteolysis (pelvis, sacrum)

  • expansile osteolytic lesions (ballooning) in ribs, pelvis, long bones

    • P.125


  • soft-tissue mass adjacent to bone destruction (= extrapleural + paraspinal mass adjacent to ribs / vertebral column)

  • periosteal new-bone formation exceedingly rare

  • involvement of mandible (rarely affected by metastatic disease)

  • sclerosis may occur after chemotherapy, radiotherapy, fluoride administration

  • sclerotic form of multiple myeloma (1 3%)

    • solitary sclerotic lesion: frequently in spine

    • diffuse sclerosis

      Associated with POEMS syndrome:

      • Polyneuropathy

      • Organomegaly

      • Endocrine abnormalities

      • Myeloma, sclerotic

      • Skin changes

  • MR (recognition dependent on knowledge of normal range of bone marrow appearance for age):

    • hypointense multiple focal areas on T1WI (25%)

    • hyperintense multiple focal areas on T2WI (53%)

    • absence of fatty infiltration (nonspecific)

  • SENSITIVITY OF BONE SCANS VS. RADIOGRAPHS

    Radiographs: in 90% of patients and 80% of sites
    Bone scan: in 75% of patients and 24 54% of sites
    Gallium scan: in 55% of patients and 40% of sites

    • 30% of lesions only detected on radiographs

    • 10% of lesions only detected on bone scans

      Cx: (1) Renal involvement frequent
        (2) Predilection for recurrent pneumonias (leukopenia)
        (3) Secondary amyloidosis in 6 15%
        (4) Pathologic fractures occur often
      Prognosis: 20% 5-year survival; death from renal insufficiency, bacterial infection, thromboembolism

  • DDx:

    • with osteopenia:

      • Postmenopausal osteoporosis

      • Hyperparathyroidism

    • with lytic lesion:

      • Metastatic disease

      • Amyloidosis

      • Myeloid metaplasia

    • with sclerotic lesion:

      • Osteopoikilosis

      • Lymphoma

      • Osteoblastic metastasis

      • Mastocytosis

      • Myelosclerosis

      • Fluorosis

      • Lymphoma

      • Renal osteodystrophy

Myelomatosis

  • generalized deossification without discrete tumors

  • vertebral flattening

Musculotendinous Injury

Muscle Contusion

Cause: direct trauma, usually by blunt object
Site: deep within muscle belly

  • injury at point of impact

  • NO architectural changes

  • feathery appearance of diffuse muscle edema

  • increased muscle girth

  • deep intramuscular hematoma (with severe trauma resulting in disruption of muscle fibers)

Myotendinous Strain

Cause: single traumatic event from excessive stretching

  • Susceptibility factors:

    • muscle composed of (fast contracting) type II fibers

    • fusiform shape of muscle

    • extension across two joints

    • superficial location of muscle

    • eccentric muscle action

      Site: myotendinous junction (= weakest point of musculotendinous unit)

  • Classification:

    • 1 degree = stretch injury (some fiber disruptions)

      • no loss of muscle function

        Path: interstitial edema + hemorrhage at myotendinous junction with extension into adjacent muscle fibers

      • feathery appearance of muscle

    • 2 degree = partial tear without retraction

      • mild loss of muscle function

      • hematoma at myotendinous junction

      • perifascial fluid collection

    • 3 degree = complete rupture

      • complete loss of muscle function

      • retracted muscle tendon

      • hematoma at myotendinous junction

Acute Avulsion Injury

Cause: forceful unbalanced often eccentric muscle contraction
Path: periosteal stripping with hematoma at tendon attachment site
Site: at tendon insertion

  • loss of function, severe tenderness

  • waviness + retraction of the torn end of tendon with fragment of bone / cartilage

Myelofibrosis

  • = MYELOSCLEROSIS = AGNOGENIC MYELOID METAPLASIA = MYELO-PROLIFERATIVE SYNDROME = PSEUDOLEUKEMIA

  • = hematologic disorder of unknown etiology with gradual replacement of bone marrow elements by fibrotic tissue

  • Characterized by:

    • extramedullary hematopoiesis

    • progressive splenomegaly

    • anemia

    • variable changes in number of granulocytes + platelets; often predated by polycythemia vera

  • Cause:

    • primary: rare in children

    • secondary: radiation therapy / chemotherapy for leukemia or lymphoma or metastatic disease; Gaucher disease

      Age: usually >50 years
      Path: fibrous / bony replacement of bone marrow; extramedullary hematopoiesis
      Associated with: metastatic carcinoma, chemical poisoning, chronic infection (TB), acute myelogenous leukemia, polycythemia vera, McCune-Albright syndrome, histiocytosis

    • P.126


  • dyspnea, weakness, fatigue, weight loss, hemorrhage

  • normochromic normocytic anemia; polycythemia may precede myelosclerosis in 59%

  • dry marrow aspirate

    Location: red marrow containing bones in 40% (thoracic cage, pelvis, femora, humeral shafts, lumbar spine, skull, peripheral bones)

  • splenomegaly

  • widespread diffuse increase in density (ground glass)

  • jail-bar ribs

  • sandwich / rugger jersey spine

  • generalized increase in bone density in skull + obliteration of diploic space; scattered small rounded radiolucent lesions; or combination of both

  • MR:

    • hypointense marrow on T1WI + T2WI

    • signal intensity slightly higher than muscle on STIR

  • NUC:

    • diffuse increased uptake of bone tracer in affected skeleton, possibly superscan

    • increased uptake at ends of long bones

DDx: (1) With splenomegaly: chronic leukemia, lymphoma, mastocytosis
  (2) Without splenomegaly: osteoblastic metastases, fluorine poisoning, osteopetrosis, chronic renal disease

Myeloid Depletion

  • = APLASTIC ANEMIA

    Cause: idiopathic;? sequelae of viral infection, medication, toxin, chemo- / radiation therapy
    Path: normal marrow replaced by fat cells

  • MR:

    • high signal intensity on T1WI

    • low signal intensity on fat-suppressed T2WI

    • Best seen in areas with high percentage of hematopoietic marrow: proximal femoral metaphyses, spine

Myeloproliferative Disorders

  • = autonomous clonal disorder initiated by an acquired pluripotential hematopoietic stem cell

  • Types:

    • Polycythemia vera

    • Chronic granulomatous leukemia = chronic myelogenous leukemia

    • Essential idiopathic thrombocytopenia

    • Agnogenic myeloid metaplasia (= primary myelofibrosis + extramedullary hematopoiesis in liver + spleen)

  • Pathophysiology:

    • self-perpetuating intra- and extramedullary hematopoietic cell proliferation without stimulus

    • trilinear panmyelosis (RBCs, WBCs, platelets)

    • myelofibrosis with progression to myelosclerosis

    • myeloid metaplasia = extramedullary hematopoiesis (normocytic anemia, leukoerythroblastic anemia, reticulocytosis, low platelet count, normal / reduced WBC count)

Myositis Ossificans

  • = PSEUDOMALIGNANT OSSEOUS TUMOR OF SOFT TISSUE = EXTRAOSSEOUS LOCALIZED NONNEOPLASTIC BONE AND CARTILAGE FORMATION = MYOSITIS OSSIFICANS CIRCUMSCRIPTA = HETEROTOPIC OSSIFICATION

  • = benign solitary self-limiting ossifying soft-tissue mass typically occurring within skeletal muscle

  • Myositis is a misnomer for lack of inflammation!

    Cause: direct trauma (75%), paralysis, burn, tetanus, intramuscular hematoma, spontaneous
    Age: adolescents, young athletic adults; M > F
    Path: lesion rimmed by compressed fibrous connective tissue + surrounded by atrophic skeletal muscle (myositis = misnomer since no primary inflammation of muscle present)

  • Histo:

    • early: focal hemorrhage + degeneration + necrosis of damaged muscle; histiocytic invasion; central nonossified core of proliferating benign fibroblasts + myofibroblasts; mesenchymal cells enclosed in ground substance assume characteristics of osteoblasts with subsequent mineralization + peripheral bone formation

    • intermediate age (3 6 weeks): zone phenomenon with central area of cellular variation and atypical mitotic figures (impossible to differentiate from soft-tissue sarcoma); middle zone of immature osteoid; outer zone of well-formed mature trabeculated dense bone

  • pain, tenderness, soft-tissue mass

    Location: large muscles of extremities (80%)

    • within muscle: anterolateral aspect of thigh + arm; temporal muscle; small muscles of hands; gluteal muscle; rider's bone (adductor longus); fencer's bone (brachialis); dancer's bone (soleus); breast, elbow, knee

    • periosteal at tendon insertion: Pellegrini-Stieda disease (in / near medial (tibial) collateral ligament of knee) as a result of Stieda fracture (= avulsion injury from medial femoral condyle at origin of tibial collateral ligament)

      • [Augusto Pellegrini (1877 1958), surgeon in Florence, Italy]

      • [Alfred Stieda (1869 1945), surgeon in K nigsberg, Germany]

  • faint calcifications develop in 2 6 weeks after onset of symptoms

  • well-defined partially ossified soft-tissue mass apparent by 6 8 weeks, becoming smaller + mature by 5 6 months

  • radiolucent zone separating lesion from bone (DDx: periosteal sarcoma on stalk)

  • periosteal reaction

  • CT:

    • well-defined mineralization at periphery of lesion after 4 6 weeks + less distinct lucent center (DDx: sarcoma with ill-defined periphery + calcified ossific center)

    • diffuse ossification in mature lesion

  • MR:

    • initially heterogeneous muscle edema

    • progression to masslike region of high-signal intensity on T2WI (during first days to weeks after injury)

      P.127


      • Early phase:

        • mass with poorly defined margins

        • inhomogeneously hyperintense to fat on T2WI

        • isointense to muscle on T1WI

        • contrast enhancement

      • Intermediate phase:

        • isointense / slightly hyperintense core on T1WI, increasing in intensity on T2WI

        • rim of curvilinear areas of decreased signal intensity surrounding the lesion (= peripheral mineralization / ossification)

        • increased peritumoral signal intensity on T2WI (= edema of diffuse myositis)

        • focal signal abnormality within bone marrow (= marrow edema)

      • Mature phase:

        • well-defined inhomogeneous mass with signal intensity approximating fat

        • decreased signal intensity surrounding lesion + within (dense ossification + fibrosis, hemosiderin from previous hemorrhage)

  • NUC:

    • intense tracer accumulation on bone scan (directly related to deposition of calcium in damaged muscle)

    • in phase of mature ossification activity becomes reduced + surgery may be performed with little risk of recurrence

  • Angio:

    • diffuse tumor blush + fine neovascularity in early active phase

    • avascular mass in mature healing phase

      Prognosis: ? resorption in 1 year

  • DDx:

    • In early stages difficult to differentiate histologically + radiologically from soft-tissue sarcomas!

      • (1) Osteosarcoma

      • Synovial sarcoma

      • Fibrosarcoma

      • Chondrosarcoma

      • Rhabdomyosarcoma

      • Parosteal sarcoma (usually metaphyseal with thick densely mineralized attachment to bone)

      • Posttraumatic periostitis (ossification of subperiosteal hematoma with broad-based attachment to bone)

      • Acute osteomyelitis (substantial soft-tissue edema + early periosteal reaction)

      • Tumoral calcinosis (periarticular calcific masses of lobular pattern with interspersed lucent soft-tissue septa)

      • Osteochondroma (stalk contiguous with normal adjacent cortex + medullary space)

Myositis Ossificans Variants

Panniculitis Ossificans

Location: subcutis of mostly upper extremities

  • less prominent zoning phenomenon

Fasciitis Ossificans

Location: fascia

Fibroosseous Pseudotumor of Digits

  • = FLORID REACTIVE PERIOSTITIS

  • = nonneoplastic solitary self-limiting process of unknown pathogenesis, probably related to trauma

    Age: mean age of 32 years (range 4 64 years); M:F = 1:2

  • fusiform soft-tissue swelling / mass

    Location: predominantly tubular bones of hand + foot: fingers (2nd > 3rd > 5th)
    Site: proximal > distal > middle phalanx

  • radiopaque soft-tissue mass with radiolucent band between mass + cortex

  • visible calcifications (50%)

  • focal periosteal thickening (50%)

  • cortical erosion (occasionally)

Rx: local excision
DDx: parosteal / periosteal osteogenic sarcoma, peripheral chondrosarcoma, periosteal chondroma, soft-tissue chondroma

Nail-patella syndrome

  • = FONG DISEASE = ILIAC HORNS = FAMILIAL / HEREDITARY OSTEO-ONYCHODYSPLASIA = OSTEO-ONYCHODYSOSTOSIS = HOOD SYNDROME = ELBOW-PATELLA SYNDROME

  • = rare autosomal dominant disorder characterized by symmetrical meso- and ectodermal anomalies

    Etiology: ? enzymatic defect in collagen metabolism
    Age: evident in 2nd + 3rd decades

  • aplasia / hypoplasia of thumb + index fingernails

  • bilateral spooning / splitting / ridging of fingernails

  • abnormal gait

  • abnormal pigmentation of iris

  • renal dysfunction (secondary to abnormal glomerular basement membrane): proteinuria, hematuria, failure later in life

  • bilateral posterior iliac horns in 80% (occasionally capped by an epiphysis) DIAGNOSTIC

  • flared iliac crest with protuberant anterior iliac spines

  • genu valgum due to asymmetrical development of femoral condyles

  • prominent tibial tubercles

  • fragmentation / hypoplasia / absence of patella; frequently with recurrent lateral dislocations

  • radial head / capitellum hypoplasia with subluxation / dislocation of radial head dorsally and increased carrying angle of elbow (DDx: congenital dislocation of radial head)

  • clinodactyly of 5th finger

  • short 5th metacarpal

  • flexion contractures of hip, knee, elbow, fingers, foot

  • deltoid, triceps, quadriceps hypoplasia

  • mandibular cysts (occasionally)

  • scoliosis

  • renal osteodystrophy

DDx: (1) Seckel syndrome = bird-headed dwarfism
  (2) Popliteal pterygium syndrome (absence of patella, toenail dysplasia)

Necrotizing Fasciitis

Incidence: 500 cases in literature
Age: 58 14 years; M>F
Cause: deep internal infection / malignancy (perforated duodenal ulcer / retroperitoneal appendix, retroperitoneal / perirectal infection, infiltrating rectal / sigmoid carcinoma
Predisposed: patients with diabetes, cancer, alcohol / drug abuse, poor nutrition
Organism: Staphylococcus, E. coli, Bacteroides, Streptococcus, Peptostreptococcus, Klebsiella, Proteus, C. perfringens (5 15%) (multiple organisms in 75%)
Histo: necrotic superficial fascia, leukocytic infiltration of deep fascial layers; fibrinoid thrombosis of arterioles + venules with vessel wall necrosis; microbial infiltration of destroyed fascia

P.128


  • indolent (1 21 days delay before diagnosis)

  • nonspecific symptoms: severe pain, fever, leukocytosis, shock, altered mental status

  • crepitus (50%), overlying skin may be completely intact

    Location: lower extremity, arm, neck, back, male perineum / scrotum (= Fournier gangrene)

  • asymmetric fascial thickening with fat stranding (80%) from fluid

  • gas in soft-tissues dissecting along fascial planes from gas-forming organisms (in 55%)

  • associated deep abscess (35%)

  • secondary muscle involvement

Prognosis: poor with delay in diagnosis
Rx: extensive surgical d bridement
DDx: (1) Myonecrosis (infection originating in muscle)
  (2) Fasciitis-panniculitis syndromes (chronic swelling of skin + underlying soft tissues + fascial planes in arm + calf)
  (3) Soft-tissue edema of CHF / cirrhosis (symmetrical diffuse fat stranding)

Neuropathic Osteoarthropathy

  • = Neurotrophic Joint = Charcot Joint = Osteoarthritis with a vengeance

  • = progressive degenerative + destructive joint disorder in patients with abnormal pain sensation + proprioception

  • Cause:

    • Congenital

      • Myelomeningocele

      • Congenital indifference to pain = asymbolia

      • Familial dysautonomia (Riley-Day syndrome)

      • Hereditary sensory and motor neuropathy (Charcot-Marie-Tooth disease)

    • Acquired

      • central neuropathy

        • Injury to brain / spinal cord

        • Syringomyelia (in 1/3 of patients): shoulder, elbow

        • Neurosyphilis = tabes dorsalis (in 15 20% of patients): hip, knee, ankle, tarsals

        • Spinal cord tumors / infection

        • Extrinsic compression of spinal cord

        • Multiple sclerosis

        • Alcoholism

      • peripheral neuropathy

        • Diabetes mellitus (most common cause, although incidence low): midfoot, tarsometatarsal joints (middle cuneiform + base of 2nd metatarsal bone first affected), intertarsal joints, subtalar joints, metatarsophalangeal joints, ankle

        • Peripheral nerve injury

        • Peripheral nerve tumor

        • Leprosy (Hansen disease)

        • Poliomyelitis

      • others

        • Scleroderma, Raynaud disease, Ehlers-Danlos syndrome

        • Rheumatoid arthritis, psoriasis

        • Amyloid infiltration of nerves, adrenal hypercorticism

        • Uremia

        • Pernicious anemia

    • Iatrogenic

      • Prolonged use of pain-relieving drugs

      • Intraarticular / systemic steroid injections

      mnemonic: DS6

      • Diabetes

      • Syphilis

      • Steroids

      • Spinal cord injury

      • Spina bifida

      • Syringomyelia

      • Scleroderma

  • Pathophysiology:

    • Loss of proprioception with sensory deficits arising in the spinal cord / peripheral nerves

      • Neurotraumatic theory

        • = repetitive trauma with absence of normal protective sensory feedback

      • Neurovascular theory

        • = absence of neural stimuli leads to a loss of sympathetic tone resulting in vasodilatation and hyperemia, which promotes bone resorption + weakening of subchondral bone

  • Pathology:

    • atrophic pattern (most common):

      • joint destruction, resorption of fragments (osteoclasts + macrophages remove bone + cartilage debris), dissolution / amputation of periarticular bones, joint effusion

      • notable absence of osteosclerosis + osteophyte formation

        Associated with: syringomyelia, peripheral nerve lesion, also in diabetes
        Location: non-weight-bearing joints of upper extremity
        DDx: surgical amputation, septic arthritis

    • hypertrophic pattern (only sensory nerves affected):

      • joint destruction, fragmentation of bone, periarticular bony debris

      • osteosclerosis + osteophyte formation (early, attaining enormous size)

        DDx: severe osteoarthritis

    • mixed pattern

    • common to both:

      • joint disorganization, large persistent bloody joint effusion

  • no history of trauma

  • swollen + warm joint with normal WBC count + ESR (infection may coexist)

  • usually painless joint; pain at presentation (in 1/3) with decreased response to deep pain + proprioception

    • P.129


  • joint changes frequently precede neurologic deficit

  • synovial fluid: frequently xanthochromic / bloody, lipid crystals (from bone marrow)

  • persistent joint effusion (first sign)

  • narrowing of joint space

  • speckled calcification in soft tissue (= calcification of synovial membrane)

  • fragmentation of eburnated subchondral bone

  • NO juxtaarticular osteoporosis (unless infected)

  • bag-of-bones appearance in late stage (= marked deformities around joint)

    mnemonic: 6 Ds

    • Dense subchondral bone (= sclerosis)

    • Degeneration (= attempted repair by osteophytes)

    • Destruction of articular cortex (with sharp margins resembling those of surgical amputation)

    • Deformity ( pencil point deformity of metatarsal heads)

    • Debris (loose bodies)

    • Dislocation (nontraumatic)

  • subluxation of joints (laxity of periarticular soft tissues)

  • progressive rapid bone resorption

  • joint distension (by fluid, hypertrophic synovitis, osteophytes, subluxation)

  • fracture: healing with exuberant bizarre callus formation

  • MR:

    • decreased signal intensity in bone marrow on T1WI + T2WI (due to osteosclerotic changes)

  • @ Shoulder

    Cause: syringomyelia, cord trauma with paraplegia

    • shoulder mass (due to fluid distension)

    • amputated appearance of proximal humerus

    • dislocation

    • large joint effusion

    • fragmented osseous debris in joint capsule + subacromial-subdeltoid bursa

      DDx: chondrosarcoma

  • @ Hands + feet

    Cause: leprosy (due to trauma + secondary bacterial infection)

    • claw hand / claw toes

    • licked candy cane appearance of metatarsal bone / tapered phalanx (due to concentric bone atrophy with decrease in bone length + width)

      DDx: diabetes mellitus, frostbite, pernicious anemia, scleroderma, syringomyelia, tabes dorsalis, familial sensory neuropathy

  • @ Spine (involved in 6 21%)

    Cause: traumatic spinal cord injury, inadequately treated syphilis, amyloidosis, congenital insensitivity to pain, diabetes mellitus
    Site: thoracolumbar junction, lumbar spine

    • disk space narrowing

    • osteolysis / sclerosis of vertebrae + facet joints

    • subluxation

    • abrupt curvature

    • scoliosis

    • paraspinous soft-tissue calcification

    • large hypertrophic beaking endplate osteophytes

    • extensive osseous fragmentation with extension beyond confines of vertebral body margin into paraspinous musculature + into spinal canal

      DDx: vertebral osteomyelitis, metastasis, granulomatous infection

  • @ Foot + ankle

    Cause: long-term poorly controlled diabetes mellitus, syphilis

    • soft-tissue swelling, warmth, erythema

      Site: often begins in midfoot

    • vascular calcifications

    • subluxation (starting at 2nd tarsometatarsal joint)

    • avulsion fracture of posterior tubercle of calcaneus

    • subchondral fracture of head of 2nd metatarsal

    • talonavicular displacement with midfoot arthropathy

DDx: osteomyelitis, septic arthritis (usually involve single joint)

Nodular Tenosynovitis

  • = GIANT CELL TUMOR OF TENDON SHEATH

  • = benign proliferative lesion of synovial origin viewed as an extraarticular form of PVNS

    Age: young adult
    Path: very cellular tumor with a capsule that separates the tumor into lobules
    Histo: multinucleated giant cells, macrophages, fibroblasts, xanthoma cells, varying amounts of hemosiderin
    Location: hand, occasionally ankle / foot
      One of the most common tumors of the hand!
    Site: tendon sheath, joint capsule, bursa, ligament

  • lobulated lesion with well-defined nodules up to 4 cm in size

  • located along tendon sheath (CHARACTERISTIC)

  • bone erosion (15%)

  • MR:

    • low signal intensity on T1WI + T2WI (hemosiderin deposition)

    • homogeneous contrast enhancement

DDx: (1) Florid proliferative synovitis (diffuse infiltrative form of GCT = extraarticular subtype of PVNS)
  (2) Pigmented villonodular synovitis
  (3) Desmoid tumor
  (4) Malignant fibrous histiocytoma

Nonossifying Fibroma

  • = FIBROXANTHOMA = NONOSTEOGENIC FIBROMA = XANTHOMA = XANTHOGRANULOMA OF BONE = FIBROUS METAPHYSEAL-DIAPHYSEAL DEFECT = FIBROUS MEDULLARY DEFECT

    Incidence: up to 40% of all children >2 years of age
    Etiology: lesion resulting from proliferative activity of a fibrous cortical defect that has expanded into medullary cavity
    Histo: interlacing whorled bundles of spindle-shaped fibroblasts + scattered multinucleated giant cells + foamy xanthomatous cells, variable degree of hemosiderin; usually cellular with only small amounts of collagen
    Age: 8 20 years; 75% in 2nd decade of life

  • usually asymptomatic; pain if large

    Location: shaft of long bone; mostly in bones of lower extremity, especially about knee (distal femur + proximal tibia); distal tibia; fibula
    Site: eccentric metaphyseal, several cm shaftward from epiphysis, mostly intramedullary, rarely purely diaphyseal

    • P.130


  • multilocular ovoid bubbly osteolytic area

  • alignment along long axis of bone, about 2 cm in length

  • dense sclerotic border toward medulla; V- or U-shaped at one end

  • endosteal scalloping + thinning overlying bulge

  • migrates toward center of diaphysis

  • resolves with age

  • NUC:

    • minimal / mild uptake on bone scan

  • MR:

    • 80% hypointense on T1WI + T2WI (extensive hypocellular fibrous tissue, hemosiderin pigment)

    • 20% hypointense on T1WI + hyperintense on T2WI (massive aggregation of foamy histiocytes)

    • peripheral hypointense rim + internal septation (marginal reactive sclerosis + trabeculation)

    • intense contrast enhancement (in 80%) / marginal septal enhancement (in 20%) on T1WI

CAVE: lesions >33 mm long involving >50% of the transverse bone diameter need observation
Prognosis: spontaneous healing in most cases
Cx: (1) Pathologic fracture (not uncommon)
  (2) Hypophosphatemic vitamin D resistant rickets + osteomalacia (tumor may secrete substance that increases renal tubular resorption of phosphorus)
DDx: (1) Adamantinoma (midshaft of tibia)
  (2) Chondromyxoid fibroma (bulging of cortex more striking, hyperintense on T2WI)
  (3) Fibrous dysplasia (internal septations rare)
  (4) Aneurysmal bone cyst (heterogeneously hyperintense with fluid-fluid levels)
  (5) Intraosseous ganglion (hyperintense on T2WI)

Multiple Fibroxanthomas (in 8 10%)

Associated with: neurofibromatosis, fibrous dysplasia, Jaff -Campanacci syndrome

Jaff -Campanacci Syndrome

  • = nonossifying fibroma with extraskeletal manifestations in children

  • mental retardation

  • hypogonadism

  • ocular defect

  • cardiovascular congenital defect

  • caf -au-lait spots

Noonan Syndrome

  • = PSEUDO TURNER = MALE TURNER SYNDROME

  • = phenotype similar to Turner syndrome but with normal karyotype (occurs in both males + females)

  • Striking familial incidence

  • short / may have normal height

  • webbed neck

  • agonadism / normal gonads

  • delayed puberty

  • mental retardation

  • osteoporosis

  • retarded bone age

  • cubitus valgus

  • @ Skull

    • mandibular hypoplasia with dental malocclusion

    • hypertelorism

    • biparietal foramina

    • dolichocephaly, microcephaly / cranial enlargement

    • webbed neck

  • @ Chest

    • sternal deformity: pectus excavatum / carinatum

    • right-sided congenital heart disease (valvar pulmonic stenosis, ASD, eccentric hypertrophy of left ventricle, PDA, VSD)

    • coronal clefts of spine

    • may have pulmonary lymphangiectasis

  • @ Gastrointestinal tract

    • intestinal lymphangiectasia

    • eventration of diaphragm

    • renal malrotation, renal duplication, hydronephrosis, large redundant extrarenal pelvis

DDx: Turner syndrome (mental retardation rare, renal anomalies frequent)

Ochronosis

  • = ALKAPTONURIA

  • = inherited absence of homogentisic acid oxidase with excessive homogentisic acid production + deposition in connective tissue including cartilage, synovium, and bone

    Histo: black-pigmented cartilage subject to deterioration resulting in calcification + denudation of cartilaginous tissue

  • M:F = 2:1

  • black pigment in soft tissues (in 2nd decade): yellowish skin; gray pigmentation of sclera; bluish tinge of ears + nose cartilage

  • alkaptonuria with black staining of diapers

  • heart failure, renal failure (pigment deposition)

  • @ Spine

    Age: middle age
    Site: lumbar region with progressive ascension

    • laminated calcification of multiple intervertebral disks

    • severe narrowing of intervertebral disk space

    • multiple vacuum phenomena (common)

    • osteoporosis of adjoining vertebrae

    • massive osteophytosis + ankylosis of spine (in older patient)

    • spotty calcifications in tissue anterior to vertebral bodies

  • @ Joints

    • hypertrophic changes in humeral head

    • severe premature progressive osteoarthritic changes in shoulder, knee, hip, spine of young patients

    • intraarticular osseous bodies

    • small calcifications in paraarticular soft tissues + tendon insertions

Orodigitofacial Syndrome

  • = OROFACIODIGITAL SYNDROME

  • = group of heterogeneous defects, probably representing varying expressivity, involving face, oral cavity, and limbs

    Etiology: autosomal trisomy of chromosome No. 1 with 47 chromosomes; X-linked dominant
    Sex: nuclear chromatin pattern female (lethal in male)
    Associated with: renal polycystic disease

    • P.131


  • mental retardation

  • hypertelorism

  • cleft lip + tongue, lingual hamartoma

  • bifid nasal tip

  • cleft in palate + jaw bone

  • hypoplasia of mandible (micrognathia) + occiput of skull

  • hypodontia

  • clinodactyly, syndactyly, brachydactyly (metacarpals may be elongated), polysyndactyly, duplication of hallux

Osgood-Schlatter Disease

  • [Robert B. Osgood (1873 1956), Boston orthopedic surgeon]

  • [Carl Schlatter (1864 1934), surgeon in Zurich, Switzerland]

  • = traumatically induced disruption of the attachment of the patellar ligament to the tibial tuberosity (chronic fatigue injury, NOT osteonecrosis); bilateral in 25%

    Age: 10 15 years; M > F
    Cause: trauma (common in sports that involve jumping, kicking, squatting) =? cartilaginous avulsion fracture,? tendinitis

  • local pain + tenderness on pressure

  • swelling of overlying soft tissue

  • soft-tissue swelling in front of tuberosity (= edema of skin + subcutaneous tissue)

  • thickening of distal portion of patellar tendon

  • indistinct margin of patellar tendon

  • increased radiodensity of infrapatellar fat pad

  • avulsion with separation of small ossicles from the developing ossification center of tibial tuberosity

  • single / multiple ossifications in avulsed fragment

  • comparison with other side (irregular development normal)

  • MR:

    • increased signal intensity at tibial insertion site of patellar tendon on T1WI + T2WI

    • distension of deep infrapatellar bursa

    • bone marrow signal changes in tibial tuberosity + tibial apophysis (rare)

Cx: nonunion of bone fragment, patellar subluxation, chondromalacia, avulsion of patellar tendon, genu recurvatum
Rx: immobilization / steroid injection
DDx: (1) Normal ossification pattern of tibial tuberosity between ages 8 14 (no symptoms)
  (2) Osteitis: tuberculous / syphilitic
  (3) Soft-tissue sarcoma with calcifications

Ossifying fibroma

  • Closely related to fibrous dysplasia + adamantinoma

    Age: 2nd 4th decade; M < F
    Histo: maturing cellular fibrous spindle cells with osteoblastic activity producing many calcific cartilaginous + bone densities
    Location: frequently in face

  • @ Mandible, maxilla

    • painless expansion of tooth-bearing portion of jaw

    • 1 5 cm well-circumscribed round / oval tumor

    • moderate expansion of intact cortex

    • homogeneous tumor matrix

    • dislodgment of teeth

  • @ Tibia

    • eccentric ground-glass lesion (resembling fibrous dysplasia)

Cx: frequent recurrences

Osteitis Condensans ILII

Incidence: 2% of population
Cause: chronic stress secondary to instability of pubic symphysis
Age: young multiparous women

  • associated with low back pain when instability of pubic symphysis present

  • triangular area of sclerosis along inferior anterior aspect of ileum adjacent to SI joint (joint space uninvolved)

  • similar triangle of reparative bone on sacral side

  • usually bilateral + symmetric; occasionally unilateral

  • sclerosis dissolves in 3 20 years following stabilization of pubic symphysis

DDx: (1) Ankylosing spondylitis (affects ilium + sacrum, joint space narrowing, involvement of other bones)
  (2) Rheumatoid arthritis (asymmetric, joint destruction)
  (3) Paget disease (thickened trabecular pattern)

Osteoarthritis

  • = DEGENERATIVE JOINT DISEASE

  • = predominantly noninflammatory degeneration of cartilage in synovial joints

    Cause: (1) abnormal forces acting on a normal joint (eg, slipped capital femoral epiphysis)
      (2) normal forces acting on abnormal joint due to
      (a) cartilage abnormality
      (b) subchondral bone abnormality
    Path: decreased chondroitin sulfate with age creates unsupported collagen fibrils followed by irreversible hyaline cartilage degeneration (= inability for regeneration)

  • Stages:

    • cartilage swelling + softening from damage to collagen matrix resulting in decreased proteoglycan content and aggregate size + increase in water content

    • increased cartilage thickness from proliferation of chondrocytes with increase in anabolic + catabolic activity

    • cartilage loss with continued damage due to decrease in cellular proliferation of chondrocytes resulting in fibrillation + erosion + cracking of articular cartilage

  • joint space narrowing (stage III) = inaccurate indicator of cartilage integrity

  • subchondral sclerosis / eburnation in areas of stress

  • subchondral cyst formation (geodes)

  • increased joint fluid

  • synovial inflammation (in severe osteoarthritis)

  • osteophytosis at articular margin / nonstressed area

  • MR:

    • increased signal intensity of abnormal cartilage on T2WI (= increased amount of free water)

    • morphologic defects on surface of cartilage (best seen on fat-suppressed spoiled gradient-echo MR)

    • P.132


  • @ Hand + foot

    Target area: 1st MCP; trapezioscaphoid; DIP > PIP; 1st MTP

    • loss of joint space, subchondral eburnation, marginal osteophytes, small ossicles in DIP + PIP:

      • Bouchard nodes = osteophytosis at PIP joint

      • Heberden nodes = osteophytosis at DIP joint:M:F = 1:10

    • radial subluxation of 1st metacarpal base

    • joint space narrowing + eburnation of trapezioscaphoid area

  • @ Shoulder

    • elevation of humeral head + lack of significant glenohumeral joint involvement (DDx to rheumatoid arthritis)

  • @ Hip

    • femoral + acetabular osteophytes, sclerosis, subchondral cyst formation

    • thickening / buttressing of medial femoral cortex / calcar

    • migration of femoral head

      • superolateral subluxation of femoral head

      • medial / axial subluxation protrusio acetabuli (in 20%)

      • primary hereditary protrusio = Otto pelvis (M < F)

  • @ Knee

    Location: medial > lateral femorotibial > patellofemoral compartment

    • varus deformity (M>>F)

  • @ Spine

    • sclerosis + narrowing of intervertebral apophyseal joints

    • osteophytosis usually associated with diskogenic disease

  • @ Sacroiliac joint

    • Most common disorder of sacroiliac joints

      Location: bi- / unilateral (contralateral SIJ with bad hip)

    • diffuse joint space loss

    • vacuum phenomenon

    • well-defined line of sclerosis, especially on iliac side of articulation

    • prominent bridging osteophyte at superior + inferior limits of joint

DDx: osteoblastic metastasis

Erosive Osteoarthritis

  • = inflammatory form of osteoarthrosis

    Predisposed: postmenopausal females
    Site: distribution identical to noninflammatory osteoarthritis: DIP > PIP > MCP joints of hands; radial aspect of wrist; bilateral + symmetric

  • bird-wing / sea-gull joint configuration = central erosions + osteophytosis

  • may lead to bony ankylosis

DDx: Rheumatoid arthritis, Wilson disease, chronic liver disease, hemochromatosis

Early Osteoarthritis

mnemonic: Early OsteoArthritis

  • Epiphyseal dysplasia, multiple

  • Ochronosis

  • Acromegaly

Milwaukee Shoulder

  • = association of

    • complete rotator cuff tear

    • osteoarthritic changes

    • noninflammatory joint effusion containing calcium hydroxyapatite and calcium pyrophosphate dihydrate (CPPD) crystals

    • hyperplasia of synovium

    • destruction of cartilage + subchondral bone

    • multiple osteochondral loose bodies

      Age: older women

  • frequent history of trauma

  • rapidly progressive arthritis of shoulder

  • Radiograph:

    • joint space narrowing

    • subchondral sclerosis + cyst formation

    • destruction of subchondral bone

    • soft-tissue swelling

    • capsular calcifications

    • intraarticular loose bodies

  • MR:

    • large effusion

    • complete rotator cuff tear

    • narrowing of glenohumeral joint

Rapidly Destructive Articular Disease

  • = unusual form of osteoarthritis typically involving the hip (almost always unilateral)

    Age: elderly women
    Associated with: conventional osteoarthritis in hands, wrists, knees, opposite hip

  • hip pain

  • progressive loss of joint space

  • loss of subchondral bone in femoral head + acetabulum resulting in hatchet deformity of femoral head

  • superolateral subluxation of femoral head / intrusion deformity within ilium

  • no / small osteophytes

    Prognosis: rapid destruction of hip within 14 months after onset of symptoms
    Rx: total joint replacement
    DDx: osteonecrosis, septic arthritis, neuroarthropathy, crystal-induced arthropathy

Osteoblastoma

  • = GIANT OSTEOID OSTEOMA = OSTEOGENIC FIBROMA OF BONE = OSSIFYING FIBROMA

  • = rare benign tumor with unlimited growth potential + capability of malignant transformation

    Incidence: <1% of all primary bone tumors; 3% of all benign bone tumors
    Age: mean age of 16 19 years; 6 30 years (90%); 2nd decade (55%); 3rd decade (20%); M:F = 2:1
    Path: lesion >1.5 cm; smaller lesions are classified as osteoid osteoma
    Histo: numerous multinucleated giant cells (osteoclasts), irregularly arranged osteoid + bone; very vascular connective tissue stroma with interconnecting trabecular bone; trabeculae broader + longer than in osteoid osteoma

    • P.133


  • asymptomatic in <2%

  • dull localized pain of insidious onset (84%), worse at night in 7 13%

  • response to salicylates in 7%

  • localized swelling, tenderness, decreased range of motion (29%)

  • painful scoliosis in 50% (with spinal / rib location) secondary to muscle spasm, may be convex toward side of tumor

  • paresthesias, mild muscle weakness, paraparesis, paraplegia (due to cord compression)

  • occasional systemic toxicity (high WBC, fever)

    Location: (rarely multifocal)

    • spine (33 37%): 62 94% in posterior elements, secondary extension into vertebral body (28 42%); cervical spine (31%), thoracic spine (34%), lumbar spine (31%), sacrum (3%)

    • long bones (26 32%): femur (50%), tibia (19%), humerus (19%), radius (8%), fibula (4%); unusual in neck of femur

    • small bones of hand + feet (15 26%): dorsal talus neck (62%), calcaneus (4%), scaphoid (8%), metacarpals (8%), metatarsals (8%)

    • calvarium + mandible (= cementoblastoma)

      Site: diaphyseal (58%), metaphyseal (42%); eccentric (46%), intracortical (42%), centric (12%), may be periosteal

  • similar to osteoid osteoma:

    • radiolucent nidus >2 cm (range of 2 12 cm) in size

    • well demarcated (83%)

    • stippled / ringlike small flecks of matrix calcification

    • reactive sclerosis (22 91%) / no sclerosis (9 56%)

  • progressive expansile lesion that may rapidly increase in size (25%):

    • cortical expansion (75 94%) / destruction (20 22%)

    • tumor matrix radiolucent (25 64%) / ossified (36 72%)

    • sharply defined soft-tissue component

    • thin shell of periosteal new bone (58 77%) / no periosteal reaction

  • scoliosis (35%)

  • osteoporosis due to disuse + hyperemia in talar location

  • rapid calcification after radiotherapy

  • CT:

    • multifocal matrix mineralization, sclerosis

    • expansile bone remodeling, thin osseous shell

  • NUC:

    • intense focal accumulation of bone agent (100%)

  • Angio:

    • tumor blush in capillary phase (50%)

  • MR:

    • low to intermediate signal intensity on T1WI

    • mixed intermediate to high intensity on T2WI

    • surrounding edema

      Prognosis: 10% recurrence after excision; incomplete curettage can effect cure due to cartilage production + trapping of host lamellar bone

  • DDx:

    • Osteo- / chondrosarcoma (periosteal new bone)

    • Osteoid osteoma (dense calcification + halo of bone sclerosis, stable lesion size <2 cm due to limited growth potential)

    • Cartilaginous tumors (lumpy matrix calcification

    • Giant cell tumor (no calcification, epiphyseal involvement)

    • Aneurysmal bone cyst

    • Osteomyelitis

    • Hemangioma

    • Lipoma

    • Epidermoid

    • Fibrous dysplasia

    • Metastasis

    • Ewing sarcoma

Osteochondroma

  • = OSTEOCARTILAGINOUS EXOSTOSIS

  • = developmental hyperplastic / dysplastic bone disturbance composed of cancellous bone surrounded by cortical bone; growth ends when nearest epiphyseal plate fuses

  • Most common benign growth of the skeleton!

  • Most common benign cartilage-containing tumor!

    Etiology: separation of a fragment of physeal cartilage herniating through periosteal bone cuff that surrounds the growth plate (encoche of Ranvier); the fragment continues to grow and undergoes enchondral ossification

    • microtrauma / Salter-Harris injury with in vivo transplantation of physeal tissue

    • radiation therapy (in 6 24%) with latency period of 3 17 years in patients between 8 months and 11 years of age receiving 1,500 5,500 cGy (frequently for treatment of neuroblastoma / Wilms tumor)

      • Most common benign radiation-induced tumor

        Path: continuity of lesion with marrow + cortex of host bone (HALLMARK)
        Histo: hyaline cartilage cap containing a basal surface with enchondral ossification (thin cortex + trabecular bone + marrow space)

  • continuity of bone cortex with host bone cortex

  • continuity of medullary marrow space with host bone

  • hyaline cartilaginous cap:

    • arcs / rings / flocculent calcifications on radiographs

  • growth pointing away from nearest joint + toward center of shaft:

    • at right angle on diaphyseal side of stalk

    • slope on epiphyseal side

  • CT:

    • optimal depiction of cortical + marrow continuity with host bone (PATHOGNOMONIC)

    • nonmineralized cartilage cap hypodense to muscle (in 75 80%):

      • 6 8 mm thick in skeletally mature patients

      • up to 30 mm thick in skeletally immature patients

  • MR:

    • cortical + medullary continuity (MR best modality)

    • hyaline cartilage cap very hyperintense on T2WI + of low to intermediate intensity on T1WI reflecting high water content:

      • hypointense mineralized areas of cartilage

      • hypointense periphery = perichondrium

      • slight septal + peripheral enhancement

  • US:

    • hypoechoic nonmineralized cartilaginous cap easily distinguished from muscle and fat

    • posterior acoustic shadowing for mineralized portion

    • P.134


  • NUC:

    • active lesion (predominantly in young patient)

    • quiescent lesion in older patient

      Prognosis: exostosis begins in childhood; stops growing when nearest epiphyseal center fuses
      Rx: surgical excision (2% recurrence rate, 13% complication rate [neuropraxia, arterial laceration, compartment syndrome, fracture])

  • Cx:

    • Osseous and cosmetic deformity (most frequent)

      • mechanical limitation of joint movement

      • snapping tendon / ligament

      • hematuria (irritating pubic osteochondroma)

      • saucerization / scalloping of cortex of adjacent bone due to extrinsic pressure erosion (of paired tubular bones)

      • premature osteoarthritis

      • pleural effusion / spontaneous hemothorax (due to irritating rib lesion)

    • Fracture through stalk of osteochondroma

    • Vascular compromise

      • venous / arterial stenosis

      • arterial occlusion / venous thrombosis

      • pseudoaneurysm formation:

        Cause: repetitive trauma to vessel wall
        Age: near end of normal skeletal growth
        Location: popliteal a., brachial a., superficial femoral a., posterior tibial a.

    • Neurologic compromise

      • peripheral nerve compression with entrapment neuropathy: foot drop with peroneal nerve involvement (most frequent)

      • central nerve compression: cranial nerve deficit, radiculopathy, cauda equina syndrome, cord compression with myelomalacia

        • often very narrow stalk of attachment

        • difficult imaging diagnosis owing to complex anatomy of skull base (21% TP)

        • spinal canal osteochondroma (15% FN)

    • Reactive bursa formation (in 1.5%)

      • enlarging mass overlying an osteochondroma simulating malignant transformation

        Location: scapula (>50%), lesser trochanter, shoulder

      • fluid-filled mass chondral filling defects:

        • mineralization of intrabursal chondral bodies may mimic a thick cartilage cap with growth

          Cx: inflammation, infection, hemorrhage into bursa, secondary synovial chondromatosis

    • Malignant transformation into secondary / peripheral chondrosarcoma / osteosarcoma

      Frequency: 1% in solitary osteochondroma; 3 5% in hereditary multiple osteochondromatosis
      Location: iliac bone commonest site

      • Any cartilage cap >1.5 cm thick / continued growth after skeletal maturation is suspect of malignant transformation!

        mnemonic: GLAD PAST

        • Growth after physeal closure

        • Lucency (new radiolucency)

        • Additional scintigraphic activity

        • Destruction (cortical)

        • Pain after puberty

        • And

        • Soft-tissue mass

        • Thickened cartilaginous cap >1.5 cm

Osteochondromatous Variants

  • Dysplasia epiphysealis hemimelica

  • Subungual exostosis

  • Turret exostosis

  • Traction exostosis (at tendinous attachments)

  • Bizarre parosteal osteochondromatous proliferation = Nora lesion

  • Florid reactive periostitis

Solitary Osteochondroma

Frequency: 1 2%; M:F = 1.6:1 3.4:1
  20 50% of benign bone tumors;
  10 15% of all bone tumors
Age: 1st 3rd decade; M:F = 1.5:1

  • incidental nontender painless mass near joints

  • symptomatic (in 75% before the age of 20 years)

Site: metaphysis of long bones; rarely diaphysis
Location: in any bone that develops by enchondromal calcification; femur (30%), tibia (15 20%), about knee (40%), humerus (10 20%), hands and feet (10%), pelvis (5%), scapula (4%), rib (3%), spine (2%, cervical [esp. C2] > thoracic [T8 > T4] > lumbar)
Type: (a) pedunculated osteochondroma = narrow stalk
  (b) sessile osteochondroma = broad base

Hereditary Multiple Exostoses

  • = DIAPHYSEAL ACLASIS (ACLASIA) = MULTIPLE OSTEOCHONDROMAS = FAMILIAL OSTEOCHONDROMATOSIS

  • = most common of osteochondrodysplasias characterized by formation of multiple exostoses

    Prevalence: 1:50,000 1:100,000;
      1:1,000 on Guam / Mariana Islands
    Genetics: autosomal dominant (incomplete penetrance in females); 3 distinct loci on chromosomes 8, 11, 19
      2/3 of affected individuals have a positive family history
    Age: forms shortly after birth; virtually all patients discovered by 12 years of age; M:F = 1.5:1.0

  • short stature (40%) due to development of exostoses at the expense of longitudinal bone growth

    Location: multiple + usually bilateral; knee (70 98%), humerus (50 98%), scapula + rib (40%), elbow (35 40%), hip (30 90%), wrist (30 60%), ankle (25 54%), hand (20 30%), foot (10 25%), pelvis (5 15%), vertebra (7%)
    Site: metaphyses of long bones near epiphyseal plate (distance to epiphyseal line increases with growth)

  • disproportionate shortening of an extremity (50%)

  • @ Upper extremity

    • pseudo-Madelung deformity:

      • ulnar shortening + longer bowed radius

      • ulnar tilt of distal radial articular surface

      • ulnar deviation of hand

      • P.135


    • dislocation of radial head

    • radioulnar synostosis

    • shortening of 4th + 5th metacarpals

    • supernumerary fingers / toes

  • @ Lower extremity

    • coxa valga (25%)

    • genu valgus (20 40%)

    • valgus deformity of ankle = tibiotalar tilt (45 54%)

    • undertubulation with widened metadiaphyseal junction:

      • Erlenmeyer flask deformity of distal femur

  • CT:

    • wavy pelvis sign = small sessile lesion create undulating cortical contour

Osteochondrosis Dissecans

  • = Osteochondritis dissecans = Osteochondral Fracture

  • = fragmentation + possible separation of a portion of the articular surface

  • Etiology:

    • subchondral fatigue fracture as a result of shearing, rotatory / tangentially aligned impaction forces / repetitive microtrauma

    • autosomal dominant trait associated with short stature, endocrine dysfunction, Scheuermann disease, Osgood-Schlatter disease, tibia vara, carpal tunnel syndrome

      Age: adolescence; M > F

  • asymptomatic / vague complaints

  • clicking, locking, limitation of motion

  • swelling, pain aggravated by movement

  • Location:

    • knee: medial (in 10% lateral) femoral condyle close to fossa intercondylaris; bilateral in 20 30%

    • humeral head

    • capitellum of elbow

    • talus

  • purely cartilaginous fragment unrecognized on plain film

  • fracture line parallels joint surface

  • mouse = osteochondrotic fragment

    Location: posterior region of knee joint, olecranon fossa, axillary / subscapular recess of glenohumeral joint

  • mouse bed = sclerosed pit in articular surface

  • soft-tissue swelling, joint effusion

  • MR:

    • focus of abnormal signal in subarticular marrow

    • defect in overlying cartilage

    • loose bodies of heterogeneous low-signal intensity in coronoid + olecranon fossa outlined by hyperintense joint fluid on T2WI

DDx: spontaneous osteonecrosis, neuroarthropathy, degenerative joint disease, synovial osteochondromatosis

Osteochondritis Dissecans of Capitellum

Age: adolescent boys 13 16 years of age
Cause: overhead throwing activity / gymnastics

  • dull poorly localized pain in elbow

  • limited extension + locking of elbow

  • lucent defect within capitellum

  • flattening of anterior border of capitellum

Osteofibrous Dysplasia

  • = entity previously mistaken for fibrous dysplasia

    Age: newborn up to 5 years
    Histo: fibrous tissue surrounding trabeculae in a whorled storiform pattern
    Location: normally confined to tibia (middiaphysis in 50%), lesion begins in anterior cortex; ipsilateral fibula affected in 20%

  • enlargement of tibia with anterior bowing

  • cortex thin / invisible

  • periosteal expansion

  • sclerotic margin (DDx: nonosteogenic fibroma, chondromyxoid fibroma)

  • spontaneous regression in 1/3

Cx: pathologic fracture in 25%, fractures will heal with immobilization; infrequently complicated by pseudarthrosis
DDx: fibrous dysplasia, Paget disease

Osteogenesis Imperfecta

  • = PSATHYROSIS = FRAGILITAS OSSIUM = LOBSTEIN DISEASE

  • = heterogeneous group of a generalized connective tissue disorder leading to micromelic dwarfism characterized by bone fragility, blue sclerae, and dentinogenesis imperfecta

    Incidence: overall in 1:28,500 (1:20,000 1:60,000) live births; M:F = 1:1
    Histo: immature collagen matrix (due to decreased / defective type I collagen synthesis)
    Genetics: mutation of COL1A1 gene on chromosome 17 and COL1A2 gene on chromosome 7

  • soft skull (caput membranaceum)

  • hyperlaxity of joints

  • blue sclerae

  • poor dentition

  • otosclerosis

  • thin loose skin

  • diffuse demineralization, deficient trabecular structure, cortical thinning

  • defective cortical bone: increase in diameter of proximal ends of humeri + femora; slender fragile bone; multiple cystlike areas

  • multiple fractures + pseudarthrosis with bowing (vertebral bodies, long bones)

  • normal / exuberant callus formation

  • rib thinning / notching

  • thin calvarium

  • sinus + mastoid cell enlargement

  • otosclerosis = otospongiosis (= thickened undermineralized otic capsule due to markedly delayed + deficient ossification of all 3 layers)

  • microfractures + deformities of middle ear ossicles (crus of stapes + handle of malleolus)

  • wormian bones persisting into adulthood

  • basilar impression (= platybasia)

  • biconcave vertebral bodies + Schmorl nodes, increased height of intervertebral disk space

  • bowing deformities after child begins to walk

Cx: (1) Impaired hearing / deafness from otosclerosis (20 60%)
  (2) Death from intracranial hemorrhage (abnormal platelet function)
Dx: chorionic villous sampling

P.136


Osteogenesis Imperfecta Type I

  • = OSTEOGENESIS IMPERFECTA TARDA

  • Most common form of mild-to-moderate disease

    Transmission: autosomal dominant with varying expression; compatible with life
    Age at presentation:

  • blue sclerae (50%)

  • presenile hearing loss (50%)

  • normal / abnormal dentinogenesis

  • infants of normal weight + length

  • osteoporosis

  • fractures in neonate (occurring during delivery)

  • OB-US:

    • marked bowing of long bones

    • NO IUGR

Osteogenesis Imperfecta Type II

  • = CONGENITAL LETHAL OSTEOGENESIS IMPERFECTA

  • = perinatal (obstetrical) lethal form

    Transmission: sporadic new dominant mutations / autosomal recessive
    Incidence: 1:54,000 births; most frequent variety

  • disease manifest at birth (in utero)

  • blue sclerae

  • hearing loss

  • ligamentous laxity + loose skin

  • shortened broad crumpled long bones

  • bone angulations, bowing, demineralization

  • localized bone thickening from callus formation

  • thin beaded ribs fractures resulting in bell-shaped / narrow chest

  • thin poorly ossified skull

  • wormian bones (present in most cases)

  • spinal osteopenia

  • platyspondyly

  • OB-US:

    • A normal sonogram after 17 weeks MA excludes the diagnosis!

    • increased through-transmission of skull (extremely poor mineralization):

      • unusually good visualization of brain surface

      • unusually good visualization of orbits

      • increased visualization of intracranial arterial pulsations

    • abnormal compressibility of skull vault with transducer

    • decreased visualization of skeleton

    • multiple fetal fractures + deformities of long bones + ribs:

      • wrinkled appearance of bone (= more than one fracture in single bone)

      • beaded ribs (callus formation around fractures)

    • abnormally short limbs

    • small thorax (collapse of thoracic cage)

    • decreased fetal movement

    • infants small for gestational age (frequent)

    • polyhydramnios + nonimmune hydrops

Prognosis: stillborn / death shortly after birth due to pulmonary hypoplasia
DDx: congenital hypophosphatasia; achondrogenesis type I; camptomelic dysplasia

Osteogenesis Imperfecta Type III

  • = SEVERE PROGRESSIVELY DEFORMING OI

    Transmission: autosomal recessive; progressively deforming disorder compatible with life

  • bluish sclerae during infancy that turn pale with time

  • joint hyperlaxity (50%)

  • hearing loss (common)

  • decreased ossification of skull

  • normal vertebrae + pelvis

  • shortened + bowed long bones

  • progressive deformities of limbs + spine into adulthood

  • rib fractures

  • multiple fractures present at birth in 2/3 of cases

  • fractures heal well

  • OB-US:

    • short + bowed long bones

    • fractures

    • humerus almost normal in shape

    • normal thoracic circumference

Prognosis: progressive limb + spine deformities during childhood / adolescence

Osteogenesis Imperfecta Type IV

Transmission: autosomal dominant; mildest form with best prognosis

  • normal scleral color

  • little tendency to develop hearing loss

  • tubular bones of normal length; mild femoral bowing may occur

  • osteoporosis

  • OB-US:

    • bowing of long bones

Osteoid Osteoma

  • = benign skeletal neoplasm composed of osteoid + woven bone less than 1.5 cm in diameter per definition

    Incidence: 12% of benign skeletal neoplasms
    Etiology: ? inflammatory response
    Histo: small nidus of osteoid-laden interconnected trabeculae with a background of highly vascularized fibrous connective tissue surrounded by zone of reactive bone sclerosis; osteoblastic rimming; indistinguishable from osteoblastoma
    Age: 10 20 years (51%); 2nd + 3rd decade (73%); 5 25 years (90%); range of 19 months 56 years; uncommon <5 and >40 years of age; M:F = 2:1; uncommon in Blacks

  • tender to touch + pressure

  • local pain (95 98%), weeks to years in duration, worse at night, decreased by activity

  • salicylates give relief in 20 30 minutes in 75 90%

  • prostaglandin E2 elevated 100 1000 normal within nidus (probable cause of pain and vasodilatation)

  • Location:

    • meta- / diaphysis of long bones (73%): upper end of femur (43%), hands (8%), feet (4%); frequent in proximal tibia + femoral neck, fibula, humerus; no bone exempt

      • P.137


    • spine (10 14%): predominantly in posterior elements (50% in pedicle + lamina + spinous process; 20% in articular process) of lumbar (59%), cervical (27%), thoracic (12%), sacral (2%) segments

      • painful scoliosis, focal / radicular pain

      • gait disturbance, muscle atrophy

    • skull, rib, ischium, mandible, patella

  • round / oval radiolucent nidus (75%) of <1.5 cm in size

  • variable surrounding sclerosis central calcification

  • painful scoliosis concave toward lesion / kyphoscoliosis / hyperlordosis / torticollis with spinal location (due to spasm)

  • may show extensive synovitis + effusion + premature loss of cartilage with intraarticular site (lymphofollicular synovitis)

  • osteoarthritis (50%) with intraarticular site 1.5 22 years after onset of symptomatology

  • regional osteoporosis (probably due to disuse)

  • Radiographically difficult areas: vertebral column, femoral neck, small bones of hand + feet

  • NUC:

    • intensely increased radiotracer uptake (increased blood flow + new-bone formation)

    • double density sign = small area of focal activity (nidus) superimposed on larger area of increased tracer uptake

  • CT (for detection + precise localization of nidus):

    • small well-defined round / oval nidus surrounded by variable amount of sclerosis

    • nidus enhances on dynamic scan

    • nidus with variable amount of mineralization (50%): punctate / amorphous / ringlike / dense

  • MR (diminished conspicuity of lesion compared with CT):

    • nidus isointense to muscle on T1WI

    • signal intensity increases to between that of muscle + fat / remains low on T2WI

    • perinidal inflammation of bone marrow (63%)

    • perinidal soft-tissue inflammation / edema (47%)

    • synovitis + joint effusion with intraarticular site

  • Angio:

    • highly vascularized nidus with intense circumscribed blush appearing in early arterial phase + persisting late into venous phase

      Prognosis: no growth progression, infrequent regression
      Rx: (1) complete surgical excision of nidus (reactive bone regresses subsequently)
        (2) percutaneous CT-guided removal
        (3) percutaneous ablation with radio-frequency electrode / laser / alcohol
      DDx: (1) Cortical osteoid osteoma: Brodie abscess, sclerosing osteomyelitis, syphilis, bone island, stress fracture, osteosarcoma, Ewing sarcoma, osteoblastic metastasis, lymphoma, subperiosteal aneurysmal bone cyst, osteoblastoma (progressive growth)
        (2) Intraarticular osteoid osteoma: inflammatory / septic / tuberculous / rheumatoid arthritis, nonspecific synovitis / legg-Calv -Perthes disease

Cortical osteoid osteoma (most common)

  • = nidus within cortex

  • solid / laminated periosteal reaction

  • fusiform sclerotic cortical thickening in shaft of long bone

  • radiolucent area within center of osteosclerosis

Cancellous Osteoid Osteoma (intermediate frequency)

  • = intramedullary

  • Intraarticular lesion difficult to identify with delay in diagnosis of 4 months 5 years!

    Site: juxta- / intraarticular at femoral neck, vertebral posterior elements, small bones of hands + feet

  • little osteosclerosis / sclerotic cortex distant to nidus (functional difference of intraarticular periosteum)

  • joint space widened (effusion, synovitis)

Subperiosteal Osteoid Osteoma (rare)

  • = round soft-tissue mass adjacent to bone

    Site: juxta- / intraarticular at medial aspect of femoral neck, hands, feet (neck of talus)

  • juxtacortical mass excavating the cortex (bony pressure atrophy) with almost no reactive sclerosis

Osteoma

  • = benign tumor of membranous bone (hamartoma)

    Age: adult life
    Associated with: Gardner syndrome (multiple osteomas + colonic polyposis)
    Location: inner / outer table of calvarium (usually from external table), paranasal sinuses (frontal / ethmoid sinuses), mandible, nasal bones

  • well-circumscribed round extremely dense structureless lesion usually <2 cm in size

Fibrous Osteoma

  • Probably a form of fibrous dysplasia

    Age: childhood

  • less dense than osteoma / radiolucent

  • expanding external table without affecting internal table

    DDx: endostoma, bone island, bone infarct (located in medulla)

Osteomyelitis

  • = infection of bone caused by bacteria, fungi, parasites, viruses

Acute Osteomyelitis

Age: most commonly affects children

  • Organism:

    • newborns: S. aureus, group B streptococcus, Escherichia coli

    • children: S. aureus (blood cultures in 50% positive)

    • adults: S. aureus (60%), enteric species (29%), Streptococcus (8%)

    • drug addicts: Pseudomonas (86%), Klebsiella, Enterobacteriae; (57 days average delay in diagnosis)

    • sickle cell disease: S. aureus, Salmonella

    • diabetics: often multiple organisms like S. aureus, Streptococcus, E. coli, Klebsiella, Clostridia, Pseudomonas (in soil + sole of shoes)

  • Cause:

    • genitourinary tract infection (72%)

    • lung infection (14%)

    • dermal infection (14%): direct contamination from a soft-tissue lesion in diabetic patient

    • P.138


  • Pathogenesis:

    • hematogenous spread

    • direct implantation from a traumatic / iatrogenic source

    • extension from adjacent soft-tissue infection

  • Location:

    • @ Lower extremity (75%) over pressure points in diabetic foot

    • @ Vertebrae (53%)

      • lumbar (75%) > thoracic > cervical (= infectious spondylitis)

    • @ Radial styloid (24%)

    • @ Sacroiliac joint (18%)

  • leukocytosis + fever (66%)

  • Conventional radiographs (insensitive):

    • initial radiographs often normal (notoriously poor in early phase of infection for as long as 10 14 days)

    • localized soft-tissue swelling adjacent to metaphysis with obliteration of usual fat planes (after 3 10 days)

    • permeative metaphyseal osteolysis (lags 7 14 days behind pathologic changes)

    • endosteal erosion

    • intracortical fissuring

    • involucrum = cloak of laminated / spiculated periosteal reaction (develops after 20 days)

    • button sequestrum = detached necrotic cortical bone (develops after 30 days)

    • cloaca formation = space in which dead bone resides

  • CT:

    • marrow density of >+20 HU difference to healthy side indicates marrow infection

  • MR (82% sensitive, 80% specific in diabetics):

    • bone marrow hypointense on T1WI + hyperintense relative to normal fatty marrow on T2WI / STIR (= water-rich inflammatory tissue + edema fluid)

      • bone marrow edema in bones adjacent to an infected point does not reliably indicate osteomyelitis

      • periarticular bone marrow edema can be seen adjacent to joints involved by noninfectious inflammatory arthropathy / osteoarthritis

    • variable enhancement after IV administration of Gd-chelate

    • focal / linear cortical involvement hyperintense on T2WI

    • hyperintense halo surrounding cortex on T2WI = subperiosteal infection

    • hyperintense line on T2WI extending from bone to skin surface + enhancement of borders (= sinus tract)

    • cortical disruption, sequestrum

    • Abscess characteristics:

      • hyperintense enhancing rim (= hyperemic zone) around a central focus of low intensity (= necrotic / devitalized tissue) on contrast-enhanced T1WI

      • hyperintense fluid collection surrounded by hypointense pseudocapsule on T2WI + contrast enhancement of granulation tissue

      • hyperintense adjacent soft tissues on T2WI

      • fat-suppressed contrast-enhanced imaging (88% sensitive + 93% specific compared with 79% + 53% for nonenhanced MR imaging)

  • NUC (accuracy approx. 90%):

    • Ga-67 scans: 100% sensitivity; increased uptake 1 day earlier than for Tc-99m MDP

      • Gallium helpful for chronic osteomyelitis!

    • Static Tc-99m diphosphonate: 83% sensitivity 5 60% false-negative rate in neonates + children because of

      • masking effect of epiphyseal plates

      • early diminished blood flow with infection

      • spectrum of uptake pattern from hot to cold

    • Three-phase skeletal scintigraphy:

      • 92% sensitivity, 87% specificity

        Phase 1: Radionuclide angiography = perfusion phase of regional blood flow
        Phase 2: blood pool images
        Phase 3: bone uptake
        Limitations: diagnostic difficulties in children, in posttraumatic / postoperative state, diabetic neuropathy (poor blood supply), neoplasia, septic arthritis, Paget disease, healed osteomyelitis, noninfectious inflammatory process
        DDx: cellulitis (decrease in activity over time)

    • WBC-scan:

      • In-111 labeled leukocytes: best agent for acute infections

      • Tc-99m labeled leukocytes: preferred over In-111 leukocyte imaging especially in extremities

      • WBC scans have largely replaced gallium imaging for acute osteomyelitis due to improved photon flux + improved dosimetry (higher dose allowed relative to In-111) allowing faster imaging + greater resolution

  • cold area in early osteomyelitis subsequently becoming hot if localized to long bones / pelvis (not seen in vertebral bodies)

  • local increase in radiopharmaceutical uptake (positive within 24 72 hours)

Cx: (1) Soft-tissue abscess
  (2) Fistula formation
  (3) Pathologic fracture
  (4) Extension into joint
  (5) Growth disturbance due to epiphyseal involvement
  (6) Neoplasm
  (7) Amyloidosis
  (8) Severe deformity with delayed treatment

Acute Neonatal Osteomyelitis

Age: onset <30 days of age

  • little / no systemic disturbance

  • multicentric involvement more common; often joint involvement

  • bone scan falsely negative / equivocal in 70%

Acute Osteomyelitis in Infancy

Age: <18 months of age
Pathomechanism: spread to epiphysis because transphyseal vessels cross growth plate into epiphysis

  • striking soft-tissue component

  • subperiosteal abscess with extensive periosteal new bone

Cx: frequent joint involvement
Prognosis: rapid healing

P.139


Acute Osteomyelitis in Childhood

Age: 2 16 years of age

  • Pathomechanism:

    • transphyseal vessels closed; metaphyseal vessels adjacent to growth plate loop back toward metaphysis locating the primary focus of infection into metaphysis; abscess formation in medulla with cortical spread

      Location: femur, tibia

  • sequestration frequent

  • periosteal elevation (with disruption of periosteal blood supply)

  • small single / multiple osteolytic areas in metaphysis

  • extensive periosteal reaction parallel to shaft (after 3 6 weeks); may be lamellar nodular (DDx: osteoblastoma, eosinophilic granuloma)

  • shortening of bone with destruction of epiphyseal cartilage

  • growth stimulation by hyperemia + premature maturation of adjacent epiphysis

  • midshaft osteomyelitis less frequent site

  • serpiginous tract with small sclerotic rim (PATHOGNOMONIC)

Acute Osteomyelitis in Adulthood

Associated with: soft-tissue abscess, pathological fracture
Risk factors: IV drug use, previous trauma, immunosuppressed state, diabetes

  • delicate periosteal new bone

  • joint involvement common

Diabetic foot

Cause: callus / minor skin trauma (eg, toenail cutting)
Pathophysiology: pressure points callus ulceration osteomyelitis

  • Location:

    • @ typical sites: heads of 1st + 5th metatarsal bones, calcaneus, malleoli

    • @ additional sites due to neuropathic foot deformities: cuboid, midfoot (from arch collapse), dorsum of toes

  • poor healing due to vascular disease

  • MR:

    • primary osseous signs:

      • low marrow signal on T1WI + high on T2WI

      • cortical interruption

      • marrow enhancement

      • periostitis = linear edema / enhancement along outer cortical margin

    • secondary (soft-tissue) signs (in >90%):

      • ulcer = interruption of cutaneous signal

      • cellulitis

      • enhancing focal soft-tissue mass effect with edema (= phlegmon)

      • focal fluid signal with rim enhancement = abscess

      • thin linear soft-tissue signal with enhancing margins (high on T2WI) = sinus tract

  • Cx:

    • Devitalized tissue = gangrene without infection

      • focal often triangular nonenhancing area of variable signal intensit

      • central tissue usually of high signal intensity on T2WI signal voids of air

      • enhancing marginal zone

    • Bone infarct

      • sharply demarcated nonenhancing marrow

    • Spread of infection to foot compartments, tendon, joint (= septic arthritis), bone (= osteomyelitis)

DDx: Neuropathic osteoarthropathy (dislocation, disorganizaton, debris, destruction, density preserved; mildly symptomatic, joint effusion, multiple joints involved, marrow edema, periarticular enhancement; more common in ankle / Lisfranc / Chopart joints)

Chronic Osteomyelitis

  • thick irregular sclerotic bone with radiolucencies, elevated periosteum, chronic draining sinus

Sclerosing Osteomyelitis of Garr

  • = STERILE OSTEOMYELITIS

  • = low-grade nonnecrotic nonpurulent infection

    Location: mandible (most commonly)

  • focal bulge of thickened cortex (sclerosing periosteal reaction)

    DDx: osteoid osteoma, stress fracture

Chronic Recurrent Multifocal Osteomyelitis

  • = benign self-limited disease of unknown etiology

    Age: children + adolescents; M:F = 1:2
    Histo: nonspecific subacute / chronic osteomyelitis

  • pain, soft-tissue swelling, limited motion

    Location: tibia > femur > clavicle > fibula
    Site: metaphyses of long bones; often symmetric

  • small areas of bone lysis, often confluent

Brodie Abscess

  • = subacute pyogenic osteomyelitis (smoldering indolent infection)

    Organism: S. aureus (most common); cultures often negative
    Histo: granulation tissue + eburnation
    Age: more common in children; M > F
    Location: predilection for ends of tubular bones (proximal / distal tibial metaphysis most common); carpal + tarsal bones
    Site: metaphysis, rarely traversing the open growth plate; epiphysis (in children + infants)

  • lytic lesion often in an oval configuration that is oriented along the long axis of the bone

  • surrounded by thick dense rim of reactive sclerosis that fades imperceptibly into surrounding bone

  • lucent tortuous channel extending toward growth plate prior to physeal closure (PATHOGNOMONIC)

  • periosteal new-bone formation

  • adjacent soft-tissue swelling

  • may persist for many months

    • P.140


  • MR:

    • double line effect = high signal intensity of granulation tissue surrounded by low signal intensity of bone sclerosis on T2WI

    • well-defined lesion of low- to intermediate signal intensity outlined by low-signal rim on T1WI

    • generally surrounded by marrow edema

    • no / rim enhancement after IV Gd-chelate

DDx: Osteoid osteoma

Epidermoid Carcinoma

Etiology: complication of chronic osteomyelitis (0.2 1.7%)
Histo: squamous cell carcinoma (90%); occasionally: basal cell carcinoma, adenocarcinoma, fibro-sarcoma, angiosarcoma, reticulum cell sarcoma, spindle cell sarcoma, rhabdomyosarcoma, parosteal osteosarcoma, plasmacytoma
Age: 30 80 (mean 55) years; M >> F
Latent period: 20 30 (range of 1.5 72) years

  • history of childhood osteomyelitis

  • exacerbation of symptoms with increasing pain, enlarging mass

  • change in character / amount of sinus drainage

    Location: at site of chronically / intermittently draining sinus; tibia (50%), femur (21%)

  • lytic lesion superimposed on changes of chronic osteomyelitis

  • soft-tissue mass

  • pathologic fracture

  • Prognosis:

    • Early metastases in 14 20 40% (within 18 months)

    • No recurrence in 80%

Osteopathia Striata

  • = VOORHOEVE DISEASE

  • = autosomal dominant / sporadic inherited disorder

  • usually asymptomatic (similar to osteopoikilosis)

    Location: all long bones affected; the only bone sclerosis primarily involving metaphysis (with extension into epi- and diaphysis)

  • longitudinal striations of dense bone in metaphysis

  • radiating densities of sunburst appearance from acetabulum into ileum

Osteopetrosis

  • = ALBERS-SCH NBERG DISEASE = MARBLE BONE DISEASE

  • = rare hereditary disorder

Path: defective osteoclast function with failure of proper reabsorption + remodeling of primary spongiosa; bone sclerotic + thick but structurally weak + brittle
Cx: (1) Usually transverse fractures (common because of brittle bones) with abundant callus + normal healing
  (2) Crowding of marrow (myelophthisic anemia + extramedullary hematopoiesis)
  (3) Frequently terminates in acute leukemia
Rx: bone marrow transplant
DDx: (1) Heavy metal poisoning
  (2) Melorheostosis (limited to one extremity)
  (3) Hypervitaminosis D
  (4) Pyknodysostosis
  (5) Fibrous dysplasia of skull / face

Infantile Autosomal Recessive Osteopetrosis

  • = congenital more severe form

    Cause: defect on chromosome 11q13

  • failure to thrive

  • premature senile appearance of facies

  • severe dental caries

  • pancytopenia (= anemia, leukocytopenia, thrombocytopenia) due to severe marrow depression

  • cranial nerve compression (optic atrophy, deafness)

  • hepatosplenomegaly (extramedullary hematopoiesis)

  • lymphadenopathy

  • subarachnoid hemorrhage (due to thrombocytopenia)

    May be associated with: renal tubular acidosis + cerebral calcification

  • dense skeleton

  • splayed metaphyses + costochondral junctions

  • fractures from minor trauma (due to brittle bones)

    Prognosis: stillbirth, survival beyond middle life uncommon (death due to recurrent infection, massive hemorrhage, terminal leukemia)
    DDx: chronic renal failure, oxalosis, pyknodysostosis, physiologic sclerosis

Benign Adult Autosomal Dominant Osteopetrosis

Cause: defect on chromosome 1p21

  • 50% asymptomatic

  • recurrent fractures, mild anemia

  • occasionally cranial nerve palsy

  • Erlenmeyer flask deformity = clublike long bones due to lack of tubulization + flaring of ends

  • Phenotype I:

    • diffuse osteosclerosis = generalized dense amorphous structureless bones with obliteration of normal trabecular pattern; mandible least commonly involved

    • cortical thickening with medullary encroachment

  • Phenotype II:

    • bone-within-bone appearance (= endobones)

    • sandwich vertebrae / rugger-jersey spine

    • alternating sclerotic + radiolucent transverse metaphyseal lines (phalanges, ilium) as indicators of fluctuating course of disease

    • longitudinal metaphyseal striations

    • obliteration of mastoid cells, paranasal sinuses, basal foramina by osteosclerosis

    • sclerosis predominantly involving base of skull; calvaria often spared

Prognosis: normal life expectancy

Osteopoikilosis

  • = OSTEOPATHIA CONDENSANS DISSEMINATA

  • = rare sclerosing bone dysplasia with autosomal dominant inheritance pattern

    Age: no age predilection; M = F
    Histo: compact bone islands (= cortical bone)

  • Associated with:

    • @ Dermatologic disorders:

      • Dermatofibrosis lenticularis disseminata (Buschke-Ollendorf syndrome) = small flesh-colored papules on trunk + extremities (in 25%)

      • Scleroderma

        • P.141


      • Keloid formation

    • @ Bone abnormalities:

      • Melorheostosis

      • Osteopathia striata

  • commonly asymptomatic

    Location: metaphyses + epiphyses (rarely extending into midshaft) of long tubular bones; concentrated at glenoid + acetabulum, carpal + tarsal bones, ankle, pelvis, scapula; rare in skull, ribs, vertebral centra, mandible

  • multiple ovoid / lenticular bone islands (2 10 mm) in cancellous bone in symmetric distribution

  • long axis of lesions parallel to long axis of bone

  • bone scintigraphic activity rare

  • MR signal characteristics equal to cortical bone

Prognosis: not progressive, no change after cessation of growth
DDx: (1) Epiphyseal dysplasia (metaphyses normal)
  (2) Melorheostosis (diaphyseal involvement)
  (3) Mastocytosis
  (4) Tuberous sclerosis
  (5) Osteoblastic metastases

Osteosarcoma

  • Most common malignant primary bone tumor in young adults + children; 2nd most common primary malignant bone tumor after multiple myeloma

    Prevalence: 4 5:1,000,000; 15% of all primary bone tumors confirmed at biopsy

  • Types & Frequency:

    • Conventional osteosarcoma:

      • high-grade intramedullary 75%

      • telangiectatic 4.5 11%

      • low-grade intraosseous 4 5%

      • small cell 1 4%

      • osteosarcomatosis 3 4%

      • gnathic 6 9%

    • Surface / juxtacortical osteosarcoma: 4 10%

      • intracortical rare

      • parosteal 65%

      • periosteal 25%

      • high-grade surface 10%

    • Extraskeletal 4%

    • Secondary osteosarcoma 5 7%

      Work-up: local staging by MR before biopsy; distant staging with bone scan + chest CT
      Prognosis: dependent on age, sex, tumor size, site, classification; best predictor is degree of tissue necrosis in postresection specimen following chemotherapy (91% survival with tumor necrosis >90%, 14% survival with <90% tumor necrosis)

Extraskeletal Osteosarcoma

  • = located within soft tissue without attachment to bone / periosteum

    Incidence: 1.2% of soft-tissue sarcomas
    Histo: variable amounts of neoplastic osteoid + bone + cartilage; frequently associated with fibrosarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor
    Mean age: 50 years; 94% >30 years of age; M > F
    Location: lower extremity (thigh in 42 47%), upper extremity (12 23%), retroperitoneum (8 17%), buttock, back, orbit, submental, axilla, abdomen, neck, kidney, breast

  • slowly growing firm soft-tissue mass

  • painful + tender (25 50%)

  • history of trauma (12 31%): in preexisting myositis ossificans / site of intramuscular injection

  • elevated levels of alkaline phosphatase (prognostic)

  • often deep-seated + fixed soft-tissue tumor (average diameter of 9 cm)

  • focal / massive area of mineralization (>50%)

  • faint moderate inhomogeneous enhancement

  • increased radionuclide uptake on bone scan

  • Prognosis:

    • multiple local recurrences (in 80 90%) after interval of 2 months to 10 years

    • metastases after interval of 1 month to 4 years: lungs (81 100%), lymph nodes (25%), bone, subcutis, liver

    • death within 2 3 years (>50%) with tumor size as major predictor

High-grade Intramedullary Osteosarcoma

  • = CENTRAL OSTEOSARCOMA = CONVENTIONAL OSTEOSARCOMA

    Histo: arising from undifferentiated mesenchymal tissue; forming fibrous / cartilaginous / osseous matrix (mostly mixed) that produces osteoid / immature bone
      (a) osteoblastic (50 80%)
      (b) chondroblastic (5 25%)
      (c) fibroblastic-fibrohistiocytic (7 25%)
    Age: bimodal distribution 10 25 years and >60 years; 21% <10 years; 68% <15 years; 70% between 10 and 30 years; M:F = 3:2 to 2:1;
      >35 years: related to preexisting condition

  • painful swelling (1 2 months' duration)

  • fever (frequent)

  • slight elevation of alkaline phosphatase

  • diabetes mellitus (paraneoplastic syndrome) in 25%

    Location: long bones (70 80%), femur (40 45%), tibia (16 20%); 50 55% about knee; proximal humerus (10 15%); facial bones (8%); cylindrical bone <30 years; flat bone (ilium) >50 years
    Site: origin in metaphysis (90 95%) / diaphysis (2 11%) /epiphysis (<1%); growth through open physis with extension into epiphysis (75 88%)
    Doubling time: 20 30 day

  • usually large bone lesion of >5 6 cm when first detected

  • cloudlike density (90%) / almost normal density / osteolytic (fibroblastic type)

  • aggressive periosteal reaction: sunburst / hair-on-end / onion-peel = laminated / Codman triangle

  • moth-eaten bone destruction + cortical disruption

  • soft-tissue mass with tumor new bone (osseous / cartilaginous type)

  • transphyseal spread before plate closure (75 88%); physis does NOT act as a barrier to tumor spread

    • P.142


  • spontaneous pneumothorax (due to subpleural metastases)

  • NUC (bone scintigraphy):

    • intensely increased activity on blood flow, blood pool, delayed images (hypervascularity, new-bone formation)

    • soft-tissue extension demonstrated, especially with SPECT

    • bone scan establishes local extent (extent of involvement easily overestimated due to intensity of uptake), skip lesions, metastases to bone + soft tissues

  • CT:

    • soft-tissue attenuation (nonmineralized portion) replacing fatty bone marrow

    • low attenuation (higher water content of chondroblastic component / hemorrhage / necrosis)

    • very high attenuation (mineralized matrix)

  • MR (preferred modality):

    • tumor of intermediate signal intensity on T1WI + high signal intensity on T2WI

    • clearly defines marrow extent (best on T1WI), vascular involvement, soft-tissue component (best on T2WI)

  • Evaluate for:

    • extent of marrow + soft-tissue involvement

    • invasion of epiphysis

    • joint (19 24%) + neurovascular involvement

    • viable tumor + mineralized matrix for biopsy

  • Metastases (in 2% at presentation):

    • hematogenous lung metastases (15%): calcifying; spontaneous pneumothorax secondary to subpleural cavitating nodules rupturing into pleural space

    • lymph nodes, liver, brain (may be calcified)

    • skeletal metastases uncommon (unlike Ewing sarcoma); skip lesions = discontinuous tumor foci in marrow cavity in 1 25%

      Cx: (1) pathologic fracture (15 20%)
        (2) radiation-induced osteosarcoma (30 years delay)
      Rx: chemotherapy followed by wide surgical resection
      Prognosis: 60 80% 5-year survival

    • amputation: 20% 5-year survival; 15% develop skeletal metastases; 75% dead within <2 years

    • multidrug chemotherapy: 55% 4-year survival more proximal lesions carry higher mortality (0% 2-year survival for axial primary)

    • Predictors of poor outcome:

      • metastasis at presentation, soft-tissue mass >20 cm, pathologic fracture, skip lesions in marrow

    • Predictors of poor response to chemotherapy:

      • no change / increase in size of soft-tissue mass, increase in bone destruction

DDx: Osteoid osteoma, sclerosing osteomyelitis, Charcot joint

High-grade Surface Osteosarcoma

Location: femur, humerus, fibula
Site: diaphysis

  • similar to periosteal osteosarcoma

  • often involves entire circumference of bone

  • frequent invasion of medullary canal

Prognosis: identical to conventional intramedullary osteosarcoma

Intracortical Osteosarcoma

  • Rarest form of osteosarcoma

    Histo: sclerosing variant of osteosarcoma which may contain small foci of chondro- or fibrosarcoma
    Location: femur, tibia

  • tumor <4 cm in diameter

  • intracortical geographic bone lysis

  • tumor margin may be well defined with thickening of surrounding cortex

  • metastases in 29%

Low-grade Intraosseous Osteosarcoma

  • = WELL-DIFFERENTIATED / SCLEROSING OSTEOSARCOMA

    Path: penetration among bony trabeculae; fibrous stroma sometimes lacking nuclear atypia + pleomorphism; highly variable amount of tumor osteoid production; may be misinterpreted as fibrous dysplasia
    Age: most frequently 3rd decade; M:F = 1:1

  • protracted clinical course with nonspecific symptoms

    Location: about the knee; femur involved in 50%
    Site: metaphysis; often with extension into epiphysis

  • may have well-defined margins + sclerotic rim

  • diffuse sclerosis

  • expansile remodeling of bone

  • subtle signs of aggressiveness: bone lysis, focally indistinct margin, cortical destruction, soft-tissue mass, periosteal reaction

N.B.: the relatively benign appearance has resulted in misdiagnosis as a benign entity!
Cx: transformation into high-grade osteosarcoma
Prognosis: similar to parosteal osteosarcoma; 80 90% 5-year survival rate; local recurrence in 10% (due to inadequate resection)
DDx: fibrous dysplasia, nonossifying fibroma, chondrosarcoma, chondromyxoid fibroma

Osteosarcoma of Jaw

  • = GNATHIC OSTEOSARCOMA

    Average age: 34 years (10 15 years older than in conventional osteosarcoma)
    Histo: chondroblastic predominance (~50%), osteoblastic predominance (~25%); better differentiated (grade 2 or 3) than conventional osteosarcoma (grade 3 or 4)

  • simulating periodontal disease: rapidly enlarging mass, lump, swelling

  • paresthesia (if inferior alveolar nerve involved)

  • painful / loose teeth, bleeding gum

    Location: body of mandible (lytic), alveolar ridge of maxilla (sclerotic), maxillary antrum

  • osteolytic / osteoblastic / mixed pattern

  • osteoid matrix (60 80%)

  • aggressive periosteal reaction for mandibular lesion

  • soft-tissue mass (100%)

  • opacification of maxillary sinus (frequent in maxillary lesions)

Prognosis: 40% 5-year survival rate (lower probability of metastases, lower grade)
DDx: metastatic disease (lung, breast, kidney), multiple myeloma, direct invasion by contiguous tumor from oral cavity, Ewing sarcoma, primary lymphoma of bone, chondrosarcoma, fibrosarcoma, acute osteomyelitis, amelo-blastoma, Langerhans cell histiocytosis, giant cell reparative granuloma, brown tumor of HPT

P.143


Osteosarcomatosis

  • = MULTIFOCAL OSTEOSARCOMA = MULTIPLE SCLEROTIC OSTEOSARCOMA

    Frequency: 2.7 4.2% of osteosarcomas

  • Etiology:

    • multicentric type of osteosarcoma

    • multiple metastatic bone lesions

  • Classification (Amstutz):

    Type I multiple synchronous bone lesions occurring within 5 months of diagnosis + patient 18 years of age
    Type II multiple synchronous bone lesions occurring within 5 months of presentation + patient >18 years of age
    Type IIIa early metachronous metastatic osteosarcoma occurring 5 to 24 months after diagnosis
    Type IIIb late metachronous metastatic osteosarcoma occurring >24 months after diagnosis
    Age: Amstutz type I = 4 18 (mean 11) years
      Amstutz type II = 19 63 (mean 30) years
    Site: metaphysis of long bones; may extend into epiphyseal plate / begin in epiphysis

  • multicentric simultaneously appearing lesions with a radiologically dominant tumor (97%)

  • smaller lesions are densely opaque (osteoblastic)

  • lesions bilateral + symmetrical

  • early: bone islands

  • late: entire metaphysis fills with sclerotic lesions breaking through cortex

  • lesions are of same size

  • lung metastases (62%)

Prognosis: uniformly poor with mean survival of 12 (range, 6 37) months
DDx: heavy metal poisoning, sclerosing osteitis, progressive diaphyseal dysplasia, melorheostosis, osteopoikilosis, bone infarction, osteopetrosis

Parosteal Osteosarcoma

Frequency: 4% of all osteosarcomas; 65% of all juxtacortical osteosarcomas
Origin: outer layer of periosteum; slowly growing lesion with fulminating course if tumor reaches medullary canal
Histo: low-grade lesion with higher-grade regions (22 64%), invasion of medullary canal (8 59%); fibrous stroma + extensive osteoid with small foci of cartilage
Age: peak age 38 years (range of 12 58 years); 50% > age 30 (for central osteosarcoma 75% < age 30); M:F = 2:3
Location: posterior aspect of distal femur (50 65%), either end of tibia, proximal humerus, fibula, rare in other long bones
Site: metaphysis (80 90%)

  • palpable mass

  • large lobulated cauliflower-like homogeneous ossific mass extending away from cortex

  • string sign = initially fine radiolucent line separating tumor mass from cortex (30 40%)

  • tumor stalk (= attachment to cortex) grows with tumor obliterating the radiolucent cleavage plane

  • cortical thickening without aggressive periosteal reaction

  • tumor periphery less dense than center (DDx: myositis ossificans with periphery more dense than center + without attachment to cortex)

  • large soft-tissue component with osseous + cartilaginous elements

Prognosis: 80 90% 5- and 10-year survival rates (best prognosis of all osteosarcomas)
DDx: osteochondroma, myositis ossificans, juxtacortical hematoma, extraosseous osteosarcoma

Periosteal Osteosarcoma

Origin: deep layer of periosteum
Histo: intermediate-grade lesion; highly chondroblastic lesion with smaller areas of osteoid formation
Age: average 20 years (range of 13 70 years); M:F = 1.7:1
Location: tibia (40%), femur (38%), ulna and humerus (5 10%)
Site: anteromedial diaphysis of proximal tibia + middle / distal femur; limited to periphery of cortex with normal endosteal margin + medullary canal (resembles parosteal sarcoma)

  • broad-based soft-tissue mass attached to cortex over entire extent of tumor (100%):

    • tumor 7 12 cm in length, 2 4 cm in width

    • involving 50 55% of osseous circumference

  • cortical thickening (82%): solid nonaggressive (51%)

  • extrinsic scalloping of cortex (92%):

    • affecting only thickened cortex (68%)

    • involving native cortex (32%)

  • periosteal reaction (95%):

    • short spicules of new bone perpendicular to shaft extending into soft-tissue mass (51%)

    • aggressive periosteal reaction of laminated appearance / Codman triangle (11%)

    • both patterns (38%)

  • NO cortical destruction / medullary cavity invasion:

    • marrow signal abnormality on MR usually due to reactive changes unless continuous with surface component (2%)

  • additional areas of matrix calcification by CT (91%)

  • chondroblastic areas (80%) with inherent high water content of hyaline cartilage:

    • hypodense on CT compared to muscle (91%)

    • very high signal intensity on T2WI (83%)

    • Biopsy may lead to erroneous diagnosis of chondrosarcoma!

  • NM (bone scintigraphy):

    • eccentric uptake (100%)

      Prognosis: 80 90% cure rate (better prognosis than central osteosarcoma with 50% 5-year survival but worse than parosteal osteosarcoma)

    • P.144


  • DDx:

    • Juxtacortical chondrosarcoma (4 5th decade, extensive osteoid + chondroid mineralization, no perpendicular periosteal reaction)

    • Ewing sarcoma (rarely periosteal, no perpendicular periosteal reaction, soft-tissue component not mineralized + not low in attenuation + not of very high intensity)

    • Parosteal osteosarcoma (3rd + 4th decade, posterior distal metaphysis of femur, attached to bone by narrow stalk, no perpendicular periosteal reaction)

    • High-grade surface osteosarcoma (surrounds >50% of bone circumference, frequent invasion of medullary cavity, no high water content of soft-tissue mass)

Secondary Osteosarcoma

  • Most osteosarcomas in patients >60 years of age are secondary!

    Cause: malignant transformation within benign process

    • Paget disease (67 90%)

      • 0.2 7.5% of patients with Paget disease develop osteosarcoma dependent on extent of disease

    • Sequelae of irradiation (6 22%) 2 40 years ago (malignant fibrous histiocytoma most common; fibrosarcoma 3rd most common)

      • 0.02 4% of patients with radiation therapy develop osteosarcoma related to exposure dose (usually >1,000 cGy)

    • Osteonecrosis, fibrous dysplasia, metallic implants, osteogenesis imperfecta, chronic osteomyelitis, retinoblastoma (familial bilateral type)

      Path: high-grade anaplastic tissue with little / no mineralization
      Age: middle-aged / late adulthood

  • aggressive bone destruction in area of preexisting condition associated with large soft-tissue mass

Prognosis: <5% 5-year survival rate

Small-cell Osteosarcoma

Age: similar to conventional osteosarcoma; M:F = 1:1
Histo: small round blue cells (similar to Ewing sarcoma) lacking cellular uniformity and consistently producing fine reticular osteoid
Location: distal femur
Site: metaphysis with frequent extension into epiphysis; diaphysis (in 15%)

  • predominantly permeative lytic medullary lesion

  • cortical breakthrough

  • aggressive periosteal reaction

  • associated soft-tissue mass

Prognosis: extremely poor

Telangiectatic Osteosarcoma

  • = MALIGNANT BONE ANEURYSM

    Frequency: 4 11% of all osteosarcomas
    Age: 3 67 (mean 20) years; M:F = 3:2
    Path: malignant osteoid-forming sarcoma of bone with large blood-filled vascular channels
    Histo: hemorrhagic + cystic + necrotic spaces occupying >90% of the lesion before therapy; blood-filled cavernous vessels lined with osteoclastic giant cells
    Location: about knee (62%); distal femur (48%), proximal tibia (14%), proximal humerus (16%)
    Site: metaphysis (90%); extension into epiphysis (87%)

  • geographic bone destruction with a wide zone of transition

  • marked aneurysmal expansion of bone (19%)

  • fluid-fluid levels (90%)

  • nodular calcific foci of osteoid (61 81%)

  • doughnut sign = peripherally increased uptake with central photopenia on bone scan

DDx: aneurysmal bone cyst (no enhancing rim of viable tumor along lesion periphery)

Oxalosis

  • Rare inborn error of metabolism

    Etiology: excessive amounts of oxalic acid combine with calcium and deposit throughout body (kidneys, soft tissue, bone)

  • hyperoxaluria = urinary excretion of oxalic acid >50 mg/ day

  • progressive renal failure

  • osteoporosis = cystic rarefaction + sclerotic margins in tubular bones on metaphyseal side, may extend throughout diaphysis

  • erosions on concave side of metaphysis near epiphysis (DDx: hyperparathyroidism)

  • bone-within-bone appearance of spine

  • nephrocalcinosis (2 HPT: subperiosteal resorption, rugger jersey spine, sclerotic metaphyseal bands)

Cx: pathologic fractures

Pachydermoperiostosis

  • = OSTEODERMOPATHIA HYPERTROPHICANS (TOURAINE-SOLENTE-GOLE) = PRIMARY HYPERTROPHIC OSTEOARTHROPATHY

  • Autosomal dominant

    Age: 3 38 years with progression into late 20s / 30s; M >> F

  • large skin folds of face + scalp

    Location: epiphyses + diametaphyseal region of tubular bones; distal third of bones of legs + forearms (early); distal phalanges rarely involved

  • enlargement of paranasal sinuses

  • irregular periosteal proliferation of phalanges + distal long bones (hand + feet) beginning in epiphyseal region at tendon / ligament insertions

  • thick cortex, BUT NO narrowing of medulla

  • clubbing

  • may have acroosteolysis

Prognosis: self-limiting = progression ceases after several years
DDx: hypertrophic pulmonary osteoarthropathy, thyroid acropachy

Paget Disease

  • = OSTEITIS DEFORMANS

  • = multifocal chronic skeletal disease characterized by disordered and exaggerated bone remodeling

    Etiology: ? chronic paramyxoviral infection
    Prevalence: 3% of individuals >40 years; 10% of persons >80 years; higher prevalence in northern latitudes; 2nd most common disease (after osteoporosis) affecting older individuals
    Age: Caucasian >55 years (in 3%); >85 years (in 10%); unusual <40 years; M:F = 2:1
    Histo: increased resorption + increased bone formation; newly formed bone is abnormally soft with disorganized trabecular pattern ( mosaic pattern ) causing deformity

P.145


  • ACTIVE PHASE = OSTEOLYTIC PHASE

    • = intense osteoclastic activity = aggressive bone resorption with lytic lesions

      Path: replacement of hematopoietic bone marrow by fibrous connective tissue with numerous large vascular channels

    • osteoporosis circumscripta of skull

    • flame-shaped radiolucency

  • MIDDLE / MIXED PHASE (common)

    • = decreased osteoclastic activity + increased osteoblastic activity

    • coexistence of lytic + sclerotic phases

  • INACTIVE / LATE PHASE = QUIESCENT PHASE

    • = diminished osteoblastic activity with decreased bone turnover

      Path: loss of excessive vascularity

    • osteosclerosis + cortical accretion (eg, ivory vertebral body)

  • asymptomatic (1/5 3/4)

  • fatigue

  • enlarged hat size

  • peripheral nerve compression

  • neurologic disorders from compression of brainstem (basilar invagination)

  • hearing loss, blindness, facial palsy (narrowing of neural foramina) rare

  • pain from

    • primary disease process rare

    • pathologic fracture

    • malignant transformation

    • degenerative joint disease / rheumatic disorder aggravated by skeletal deformity

  • local hyperthermia of overlying skin

  • high-output congestive heart failure from markedly increased perfusion (rare)

  • increased alkaline phosphatase (increased bone formation)

  • hydroxyproline increased (increased bone resorption)

  • normal serum calcium + phosphorus

    Sites: usually polyostotic + asymmetric; pelvis (75%) > lumbar spine > thoracic spine > proximal femur > calvarium > scapula > distal femur > proximal tibia > proximal humerus
    Sensitivity: scintigraphy + radiography (60%)
      scintigraphy only (27 94%)
      radiography only (13 74%)

  • osseous expansion

  • trabecular coarsening

  • cortical thickening

  • cystlike areas (fat-filled marrow cavity / blood-filled sinusoids / liquefactive degeneration + necrosis of proliferating fibrous tissue)

  • @ Skull (involvement in 29 65%)

    • inner + outer table involved

    • diploic widening

    • osteoporosis circumscripta = well-defined lysis, most commonly in calvarium anteriorly, occasionally in long bones (destructive active stage)

    • cotton wool appearance = mixed lytic + blastic pattern of thickened calvarium (late stage)

    • basilar impression with encroachment on foramen magnum

    • deossification + sclerosis in maxilla

    • sclerosis of base of skull

  • @ Long bones (almost invariable at end of bone; rarely in diaphysis)

    • candle flame / blade of grass lysis = advancing tip of V-shaped lytic defect in diaphysis of long bone originating in subarticular site (CHARACTERISTIC)

    • lateral curvature of femur, anterior curvature of tibia (commonly resulting in fracture)

  • @ Ribs (1 4%)

  • @ Small / flat bones

    • bubbly destruction + periosteal successive layering

  • @ Pelvis

    • thickened trabeculae in sacrum, ilium; rarefaction in central portion of ilium

    • thickening of iliopectineal line

    • acetabular protrusion (DDx: metastatic disease not deforming) + secondary degenerative joint disease

  • @ Spine (upper cervical, low dorsal, midlumbar)

    • lytic / coarse trabeculations at periphery of bone

    • picture-frame vertebra = bone-within-bone appearance = enlarged square vertebral body with reinforced peripheral trabeculae + radiolucent inner aspect, typically in lumbar spine

    • ivory vertebra = blastic vertebra with increased density

    • ossification of spinal ligaments, paravertebral soft tissue, disk spaces

  • Bone scan (94% sensitive):

    • usually markedly increased uptake (symptomatic lesions strikingly positive due to increased blood flow + osteoblastic activity)

    • normal scan in some sclerotic burned-out lesions

    • marginal uptake in lytic lesions

    • enlargement + deformity of bones

  • Bone marrow scan:

    • sulfur colloid bone marrow uptake is decreased (marrow replacement by cellular fibrovascular tissue)

  • MR:

    Indications: imaging of complications (spinal stenosis, basilar impression, tumor staging)

    • areas of decreased signal intensity within marrow on T1WI + increased intensity on T2WI (= fibrovascular tissue resembling granulation tissue)

    • hypointense area / area of signal void on T1WI + T2WI (cortical thickening, coarse trabeculation)

    • reduction in size + signal intensity of medullary cavity (replacement of high-signal-intensity fatty marrow by increased medullary bone formation)

    • focal areas of higher signal intensity than fatty marrow (= cystlike fat-filled marrow spaces)

    • widening of bone

  • Cx:

    • Associated neoplasia (0.7 1 20%)

      • sarcomatous transformation into osteosarcoma (22 90%), fibrosarcoma /malignant fibrous histiocytoma (29 51%), chondrosarcoma (1 15%)

        • osteolysis in pelvis, femur, humerus

          Prognosis: <10% 5-year survival

        • P.146


      • multicentric giant cell tumor (3 10%)

        • lytic expansile lesion in skull, facial bones

      • lymphoma, plasma cell myeloma

    • Insufficiency fracture

      • banana fracture = tiny horizontal cortical infractions on convex surfaces of lower extremity long bones (lateral bowing of femur, anterior bowing of tibia);

      • compression fractures of vertebrae (soft bone despite increased density)

    • Neurologic entrapment

      • basilar impression with obstructive hydrocephalus + brainstem compression + syringomyelia

      • spinal stenosis with extradural spinal block (osseous expansion / osteosarcoma / vertebral retropulsion owing to compression fracture)

    • Early-onset osteoarthritis

      Pathogenesis: altered biomechanics across affected articulations
Rx: calcitonin, biphosphonates, mithramycin

  • Detection of recurrence:

    • in 1/3 detected by bone scan

    • in 1/3 detected by biomarkers (alkaline phosphatase, urine hydroxyproline)

    • in 1/3 by scan + biomarkers simultaneously

    • diffuse (most common) / focal increase in tracer uptake

    • extension of uptake beyond boundaries of initial lesion

DDx: osteosclerotic metastasis, osteolytic metastasis, Hodgkin disease, vertebral hemangioma

Paraosteoarthropathy

  • = HETEROTOPIC BONE FORMATION = ECTOPIC OSSIFICATION = MYOSITIS OSSIFICANS

  • Common complication following surgical manipulation, total hip replacement (62%) and chronic immobilization (spinal cord injury / neuromuscular disorders)

    Mechanism: pluripotent mesenchymal cell lays down matrix for formation of heterotopic bone similar to endosteal bone
    Causes: para- / quadriplegia (40 50%), myelomeningocele, poliomyelitis, severe head injury, cerebrovascular disease, CNS infections (tetanus, rabies), surgery (commonly following total hip replacement)
    Evolution: calcifications seen 4 10 weeks following insult; progression for 6 14 months; trabeculations by 2 3 months; stable lamellar bone ankylosis in 5% by 12 18 months

  • largest quantity of calcifications around joints, especially hip, along fascial planes

  • disuse osteoporosis of lower extremities

  • renal calculi (elevation of serum calcium levels)

  • Radiographic grading system (Brooker):

    • 0 no soft-tissue ossification

    • I separate small foci of ossification

    • II >1 cm gap between opposing bone surfaces of heterotopic ossifications

    • III <1 cm gap between opposing bone surfaces

    • IV bridging ossification

  • Bone scan:

    • tracer accumulation in ectopic bone

    • assessment of maturity for optimal time of surgical resection (indicated by same amount of uptake as normal bone)

Cx: ankylosis in 5%
Rx: 1000 2000 rad within 4 days following surgical removal

Phenylketonuria

  • High incidence of x-ray changes in phenylalanine-restricted infants:

  • metaphyseal cupping of long bones (30 50%), especially wrist

  • calcific spicules extending vertically from metaphysis into epiphyseal cartilage (DDx to rickets)

  • sclerotic metaphyseal margins

  • osteoporosis

  • delayed skeletal maturation

DDx: homocystinuria

Phosphorus Poisoning

  • Etiology:

    • ingestion of metallic phosphorus (yellow phosphorus)

    • treatment of rachitis or TB with phosphorized cod liver oil

      Location: long tubular bones, ilium

  • multiple transverse lines (intermittent treatment with phosphorus)

  • lines disappear after some years

Pierre Robin Syndrome

May be associated with: CHD, defects of eye and ear, hydrocephalus, microcephaly

  • glossoptosis

  • micrognathia = hypoplastic receding mandible

  • arched cleft palate

  • rib pseudarthrosis

Cx: airway obstruction (relatively large tongue), aspiration

Pigmented Villonodular Synovitis

  • = PVNS = benign inflammatory lesion with extensive intraarticular highly vascular synovial proliferation / benign tumor of histiocytic origin /

    Cause: frequently history of antecedent trauma
    Path: many villous / frondlike synovial proliferations
    Histo: (1) hyperplasia of undifferentiated connective tissue with multinucleated large cells ingesting hemosiderin / lipoid (foam / giant cells)
      (2) villonodular appearance of synovial membrane fibrosis
      (3) pressure erosion / invasion of adjoining bone
    Age: mainly 3rd 4th decade (range 12 68 years);
      50% <40 years; M:F=1:1

  • hemorrhagic chocolate / serosanguinous / xanthochromic joint effusion without trauma

  • insidious onset of swelling, pain of long duration

  • joint stiffness with decreased range of motion, joint locking

    Location: knee (80%) > hip > ankle > shoulder > elbow > tarsal + carpal joints; predominantly monoarticular (DDx: degenerative arthritis)

  • soft-tissue swelling around joint (effusion + synovial proliferation):

    P.147


    • joint effusion in knee, but not relevant in other joints

  • dense soft tissues (hemosiderin deposits)

  • subchondral pressure erosion (56%) at margins of joint on both sides of joint

  • multiple sites of irregular cystlike radiolucent defects due to invasion of bone

  • NO calcifications, osteoporosis, joint space narrowing (until late)

  • CT:

    • small radiographically invisible erosions

    • juxtaarticular soft-tissue mass with high attenuation

  • MR:

    • lobulated intraarticular masses of synovial tissue in a joint with effusion

    • scalloping / truncation of prefemoral fat pad

    • predominantly low signal intensity on all sequences (due to presence of iron) is CHARACTERISTIC

    • often heterogeneous low + high signal intensity on T2WI:

      • marked signal loss in periphery of lesions (magnetic susceptibility effect of hemosiderin)

        DDx: hemosiderin deposits in other diseases (eg, rheumatoid arthritis)

      • high-signal intensity areas (due to fat, effusion, edema, inflammation)

Rx: synovectomy (50% recurrence rate), arthrodesis, arthroplasty, radiation
DDx: (1) Degenerative / traumatic arthritis
  (2) Synovial sarcoma (solitary calcified mass outside joint)
  (3) Sclerosing hemangioma
  (4) Benign xanthoma
  (5) Xanthogranuloma

Intraarticular Localized Nodular Synovitis

  • = synovial lining without hemosiderin

Tenosynovial Giant Cell Tumor

  • = localized form of PVNS only involving the tendon sheath

Poland Syndrome

May be associated with: aplasia of mamilla / breast

  • Autosomal recessive

  • unilateral absence of the sternocostal head of the pectoralis major muscle

  • ipsilateral syndactyly + brachydactyly

  • rib anomalies

Poliomyelitis

  • osteoporosis

  • soft-tissue calcification / ossification

  • intervertebral disk calcification

  • rib erosion commonly on superior margin of 3rd + 4th rib (secondary to pressure from scapula)

  • bamboo spine (resembling ankylosing spondylitis)

  • sacroiliac joint narrowing

Popliteal Cyst

  • = BAKER CYST

  • = synovial cyst in the posterior aspect of knee joint communicating with posterior joint capsule

    Prevalence: 19% in general orthopedic patients, 61% in patients with rheumatoid arthritis

  • Pathophysiology:

    • formed by escape of synovial effusion into one of the bursae; fluid trapped by one-way valvular mechanism

      • Bunsen-type valve = expanding cyst compresses the communicating channel

      • ball-type valve = ball composed of fibrin + cellular debris plugs the communication channel

  • Etiology:

    • Arthritis (rheumatoid arthritis most common)

    • Internal derangement (meniscal / anterior cruciate ligament tears)

    • Pigmented villonodular synovitis

  • pseudothrombophlebitis syndrome (= pain + swelling in calf)

  • cellulitis (after leakage / rupture)

  • Location:

    • gastrocnemius-semimembranosus bursa = posterior to gastrocnemius muscle at level of medial condyle

    • supralateral bursa = between lateral head of gastrocnemius muscle + distal end of biceps muscle superior to lateral condyle (uncommon)

    • popliteal bursa = beneath lateral meniscus + anterior to popliteal muscle (uncommon)

  • communication with bursa (documented on arthrogram)

  • hypointense collection on T1WI + hyperintense on T2WI

  • Types:

    • Intact cyst

      • smooth contour

    • Dissected cyst

      • smooth contour extending along fascial planes (usually between gastrocnemius + soleus)

    • Ruptured cyst

      • leakage into calf tissues

  • DDx of other synovial cysts about the knee:

    • Meniscal cyst (at lateral / medial side of joint line; associated with horizontal cleavage tears)

    • Tibiofibular cyst (at proximal tibiofibular joint, which communicates with knee joint in 10%)

    • Cruciate cyst (surrounding anterior / posterior cruciate ligaments following ligamentous injury)

Progeria

  • = HUTCHINSON-GILFORD SYNDROME

  • = autosomal recessive inheritance; most commonly in populations with consanguineous marriages (Japanese, Jewish)

    Age: shortly after adolescence; M:F = 1:1

  • characteristic habitus + stature:

    • symmetric retardation of growth

    • absent adolescent growth spurt

    • dwarf with short stature + light body weight

    • spindly extremities with stocky trunk

    • beak-shaped nose + shallow orbits

  • premature senescence:

    • birdlike appearance

    • graying of hair + premature baldness

    • hyperpigmentation

    • voice alteration

    • diffuse arteriosclerosis

    • bilateral cataracts

    • osteoporosis

  • scleroderma-like skin changes:

    P.148


    • atrophic skin + muscles

    • circumscribed hyperkeratosis

    • telangiectasia

    • tight skin

    • cutaneous ulcerations

    • localized soft-tissue calcifications

  • endocrine abnormalities:

    • diabetes

    • hypogonadism

  • generalized osteoporosis

  • @ Skull

    • thin cranial vault

    • delayed sutural closure + wormian bones

    • hypoplastic facial bones (maxilla + mandible)

  • @ Chest

    • narrow thorax + slender ribs

    • progressive resorption with fibrous replacement of outer portions of thinned clavicles (HALLMARK)

    • coronary artery + heart valve calcifications with cardiac enlargement

  • @ Extremities & joints

    • short + slender long bones

    • coxa valga

    • valgus of humeral head

    • acroosteolysis of terminal phalanges (occasionally)

    • flexion + extension deformities of toes (hallux valgus, pes planus)

    • excessive degenerative joint disease of major + peripheral joints

    • neurotrophic joint lesions (feet)

    • widespread osteomyelitis + septic arthritis (hands, feet, limbs)

  • @ Soft tissue

    • soft-tissue atrophy of extremities

    • soft-tissue calcifications around bony prominences (ankle, wrist, elbow, knee)

    • peripheral vascular calcifications = premature atherosclerosis

Prognosis: most patients die in their 30s / 40s from complications of arteriosclerosis (myocardial infarction, stroke) or neoplasm (sarcoma, meningioma, thyroid carcinoma)
DDx: Cockayne syndrome (mental retardation, retinal atrophy, deafness, family history)

Pseudoachondroplasia

  • normal face + head

  • limb shortening

  • irregular epiphyses

  • scoliosis

  • coxa vara

  • marked shortening of bones in hands + feet

Pseudofractures

  • = LOOSER LINES = LOOSER ZONES = OSTEOID SEAMS = MILKMAN SYNDROME

  • = insufficiency stress fractures + nonunion (incomplete healing due to mineral deficiency)

    Path: area of unmineralized woven bone occurring at sites of mechanical stress / nutrient vessel entry

  • Associated with:

    • Osteomalacia / rickets

    • Paget disease ( banana fracture )

    • Osteogenesis imperfecta tarda

    • Fibrous dysplasia

    • Organic renal disease in 1%

    • Renal tubular dysfunction

    • Congenital hypophosphatasia

    • Congenital hyperphosphatasia ( juvenile Paget disease )

    • Vitamin D malabsorption / deficiency

    • Neurofibromatosis

      mnemonic: POOF

      • Paget disease

      • Osteomalacia

      • Osteogenesis imperfecta

      • Fibrous dysplasia

  • Common locations:

    • scapulae (axillary margin, lateral + superior margin), medial femoral neck + shaft, pubic + ischial rami, ribs, lesser trochanter, ischial tuberosity, proximal 1/3 of ulna, distal 1/3 of radius, phalanges, metatarsals, metacarpals, clavicle

  • typically bilateral + symmetric at right angles to bone margin

  • paralleled by marginal sclerosis in later stages

  • healing fracture with little or no callus response

  • 2 3-mm stripe of lucency at right angle to cortex (= osteoid seams formed within stress-induced infractions (PATHOGNOMONIC) + nonunion (= incomplete healing due to mineral deficiency)

Pseudohypoparathyroidism

  • = PHypoPT = congenital X-linked dominant abnormality with renal + skeletal resistance to PTH due to

    • end- organ resistance

    • presence of antienzymes

    • defective hormone

      May be associated with: hyperparathyroidism due to hypocalcemia; F > M

  • short obese stature, round face

  • mental retardation

  • corneal + lenticular opacity

  • abnormal dentition (hypoplasia, delayed eruption, excessive caries)

  • hypocalcemia + hyperphosphatemia (resistant to PTH injection)

  • normal levels of PTH

  • brachydactyly in bones in which epiphysis appears latest (metacarpal, metatarsal bones I, IV, V) (75%)

  • accelerated epiphyseal maturation resulting in dwarfism + coxa vara / valga

    Differential Signs between PHypoPT and PPHypoPT

      PHypoPT PPHypoPT
    calcification of basal ganglia 44% 8%
    soft-tissue calcifications 55% 40%
    metacarpal shortening (4 + 5 always involved) 75% 90%
    metatarsal shortening (3 + 4 involved) 70% 99%

    • P.149


  • multiple diaphyseal exostoses (occasionally)

  • calcification of basal ganglia + dentate nucleus

  • calcification / ossification of skin + subcutaneous tissue

Pseudopseudohypoparathyroidism

  • = PPHypoPT = different expression of same familial disturbance with identical clinical + radiographic features as pseudohypoparathyroidism but normocalcemic

    Cause: end-organ resistance to PTH

  • short stature, round facies

  • NO blood chemical changes (normal calcium + phosphorus)

  • normal response to injection of PTH

  • brachydactyly

Pseudoxanthoma Elasticum

  • = recessive hereditary systemic disorder characterized by degeneration of elastic tissue

  • @ Skin

    • redundant skin folds, particularly in flexor regions

    • yellowish xanthomatous papules

    • large amorphous calcific deposits in soft tissue about the joints

  • @ Eyes

    • diminished visual acuity due to alteration of chorioretinal structure

    • angioid streaks = reddish brown serrated lines extending from optic disk in a spoke-wheel fashion

  • @ Arteries

    • claudication + decreased pulses

      Histo: tissue degeneration of internal elastic lamina + medial thickening

    • lobulated appearance of arteries (similar to fibromuscular hyperplasia)

    • aneurysm formation

    • vessel calcification at early age

Cx: GI tract hemorrhage

Psoriatic Arthritis

  • Uncommon disease involving synovium + ligamentous attachments with propensity for sacroiliitis / spondylitis classified as seronegative spondyloarthropathy 6/c

    Incidence: 20% of patients with psoriasis (peripheral arthritis in 5%, sacroiliitis in 29%, peripheral arthritis + sacroiliitis in 10%)
    Path: synovial inflammation (less prominent than in rheumatoid arthritis) with early fibrosis of proliferative synovium; bony proliferation at joint margins / tendon insertions / subperiosteum

  • Types:

    • true psoriatic arthritis (31%)

    • psoriatic arthritis resembling rheumatoid arthritis (38%)

    • concomitant rheumatoid + psoriatic arthritis (31%)

  • skin rash precedes / develops simultaneously with onset of arthritis in 85%

    • Arthritis antedates dermatological changes by an interval of up to 20 years!

  • pitting, discoloration, hyperkeratosis, subungual separation, ridging of nails (in 80%)

  • positive HLA-B27 in 80%

  • negative rheumatoid factor

    Location: widely variable distribution + asymmetry with involvement of lower + upper extremities; distinctive pattern: terminal interphalangeal joints, ray distribution, unilateral polyarticular asymmetrical distribution

  • NO / minimal juxtaarticular osteoporosis (early stage); frequent osteoporosis (later stages)

  • marginal erosions

  • periosteal reaction frequent

  • intraarticular osseous excrescences

  • @ Hand + foot

    Target area: DIP, PIP, MCP

    • sausage digit = soft-tissue swelling of entire digit

    • destruction of distal interphalangeal joints (erosive polyarthritis) + osseous resorption

    • bony ankylosis (10%)

    • pencil-in-cup deformity = erosions with ill-defined margins + adjacent proliferation of periosteal new bone (CHARACTERISTIC)

    • ivory phalanx = sclerosis of terminal phalanx (28%)

    • destruction of interphalangeal joint of 1st toe with exuberant periosteal reaction + bony proliferation at distal phalangeal base (PATHOGNOMONIC)

    • poorly defined diffuse new bone formation at attachment of Achilles tendon + plantar aponeurosis

    • erosions at superior / posterior margin of calcaneus (20%)

    • acroosteolysis (occasionally)

  • @ Axial skeleton

    • floating osteophyte = large bulky vertically oriented paravertebral soft-tissue ossification (AP view):

      • ill-defined excrescence sweeping across the diskovertebral junction from midportion of one vertebra to the next

        Location: lower cervical, thoracic, upper lumbar spine; asymmetric / unilateral

    • squaring of vertebrae in lumbar region

    • sacroiliitis (40%) = (most commonly) bilateral + symmetric sacroiliac joint widening, increased density, fusion

    • apophyseal joint narrowing + sclerosis

    • atlantoaxial subluxation + odontoid abnormalities

DDx: (1) Reiter syndrome (affects only lower extremity)
  (2) Ankylosing spondylitis
  (3) Rheumatoid arthritis (bilaterally symmetric well-defined erosions, juxtaarticular osteoporosis)

Pyknodysostosis

  • = MAROTEAUX-LAMY DISEASE

  • = autosomal recessive inherited disease; probably variant of cleidocranial dysostosis

    Cause: mutation in cathepsin-K gene
    Age: children; M:F = 2:1

  • dwarfism

  • mental retardation (10%)

  • widened hands + feet

  • dystrophic nails

  • yellowish discoloration of teeth

  • characteristic facies (beaked nose, receding jaw)

  • brachycephaly + platybasia

  • wide cranial sutures, wormian bones

    • P.150


  • thick skull base

  • hypoplasia of mandible + obtuse mandibular angle

  • hypoplasia + nonpneumatization of paranasal sinuses

  • nonsegmentation of C1/2 and L5/S1

  • generalized increased density of long bones with thickened cortices (resembling osteopetrosis but with preservation of medullary canal)

  • clavicular dysplasia

  • hypoplastic tapered terminal tufts (=acroosteolysis)

  • multiple spontaneous fractures

DDx: (1) Osteopetrosis (no dwarfism, no mandibular / skull abnormality, no phalangeal hypoplasia, no transverse metaphyseal bands, anemia, Erlenmeyer flask deformity; bone-within-bone appearance)
  (2) Cleidocranial dysostosis (no dense bones / terminal phalangeal hypoplasia, short stature)

Radiation Injury to Bone

Pathogenesis: vascular compromise with obliterative endarteritis + periarteritis followed by damage to osteoblasts + osteoclasts with decreased matrix production (growing bone + periosteal new bone most sensitive)

  • Dose effects:

    • depend on age of patient, absorbed dose, size of radiation field, beam energy, fractionation

      >300 rad: microscopic changes
      >400 rad: growth retardation
      <600 1200 rad: histological recovery retained
      >1200 rad: pronounced cellular damage to chondrocytes; bone marrow atrophy + cartilage degeneration after >6 months; vascular fibrosis

  • FOCAL MARROW DEPLETION.

    Pathophysiology: marrow edema, vascular congestion, suppressed hematopoiesis; replacement of marrow elements by fibrosis + fat (complete by 3 months)

    • homogeneous high-intensity signal within radiation port on T1WI

    • occasionally bandlike appearance characterized by peripheral zone of low signal intensity (red marrow) and a central zone of high signal intensity (fatty marrow) on T1WI

  • BONE GROWTH DISTURBANCE

    • @ Appendicular skeleton

      • joint space widening (due to cartilage hypertrophy) after 8 10 months

      • growth plate widening in 1 2 months, often returning to normal by 6 months

      • permanent alteration in bone length / size (due to premature fusion of physis)

      • metaphyseal bowing

      • sclerotic metaphyseal bands

      • metaphyseal irregularity + fraying resembling rickets

      • longitudinal striations

      • overtubulation (= abnormal narrowing of the diaphyseal shaft)

        Cx: slippage of femoral / humeral epiphysis ischemic necrosis (after doses of >25 Gy)

    • @ Axial skeleton (dose of <15 Gy)

      • bone-within-bone appearance after 9 12 months

      • irreversible scalloping + irregularity of vertebral endplate with decreased height of vertebra

        • (= failure of vertical growth)

      • scoliosis concave to the side of irradiation (due to asymmetric vertebral growth + muscular fibrosis)

      • hypoplasia of ilium + ribs

      • acetabular dysplasia, coxa vara / valga

  • RADIATION OSTEITIS = OSTEORADIONECROSIS

    • = RADIATION NECROSIS

    • = bone mottling due to osteopenia + coarse trabeculation + focally increased bone density (due to attempts of osseous repair with deposition of new bone on ischemic trabeculae)

      Dose: >6,000 cGy in adults; >2,000 cGy in children
      Time of onset: 1 3 years following radiation therapy
      Location: mandible, ribs, clavicle, humerus, spine, pelvis, femur

    • focal lytic area with abnormal bone matrix:

      • radiolucency confined to radiation field with narrow zone of transition

    • periostitis

    • increased fragility with sclerosis (= pathologic insufficiency fracture)

    • cortical thinning from chronic infection

    • MR:

      • increased intensity of spinal bone marrow on T1WI + T2WI corresponding to radiation port (fatty infiltration)

    • NUC:

      • bone scan with decreased uptake in radiation field

        Cx: increased susceptibility of irradiated bone to infection
        DDx: recurrent malignancy, radiation-induced sarcoma (soft-tissue mass), infection

  • BENIGN NEOPLASM

    • Most likely in patients <2 years of age at treatment; with doses of 1600 6425 rads

    Latent period: 1.5 5 14 years

    • Osteochondroma = exostosis (exclusively in children under 2 years of age during treatment)

    • Osteoblastoma

  • MALIGNANT NEOPLASM

    • = RADIATION-INDUCED SARCOMA

      Latency period: 3 55 (average of 11 14) years
      Minimum dose: 1,660 3,000 rad
      Criteria: (a) malignancy occurring within irradiated field
        (b) latency period of >5 years
        (c) histologic proof of sarcoma
        (d) microscopic evidence of altered histology of the original lesion
      Histo: 1. Osteosarcoma (90%) = 4 11% of all osteogenic sarcomas
        2. Fibrosarcoma > chondrosarcoma > malignant fibrous histiocytoma

    • pain, soft-tissue mass, rapid progression of lesion

Reflex Sympathetic Dystrophy

  • = CAUSALGIA = SHOULDER-HAND SYNDROME = POSTTRAUMATIC OSTEOPOROSIS = SUDECK DYSTROPHY

    • P.151


  • = serious + potentially disabling condition with poorly understood origin + cause

  • Etiology:

    • Trauma in >50% (fracture, frostbite; may be trivial)

      • Affects 0.01% of all trauma patients

    • Idiopathic in 27% (immobilization, infection)

    • Myocardial ischemia in 6%

    • CNS disorders in 6%

      • Affects 12 21% of patients with hemiplegia

    • Diskogenic disease in 5%

  • burning pain, tenderness, allodynia, hyperpathia

  • soft-tissue swelling pitting edema out of proportion to degree of injury

  • dystrophic skin + nail changes

  • sudomotor changes: hyperhidrosis + hypertrichosis

  • vasomotor instability (Raynaud phenomenon, local vasoconstriction / -dilatation)

  • end-stage (after 6 12 months): contractures, atrophy of skin + soft tissues

    Location: hands and feet distal to injury

  • periarticular soft-tissue swelling

  • patchy osteopenia (50%) as early as 2 3 weeks after onset of symptoms (DDx: disuse osteopenia)

  • generalized osteopenia = ground-glass appearance with endosteal + intracortical excavation:

  • subperiosteal bone resorption

  • lysis of juxtaarticular + subchondral bone

  • preservation of joint space (DDx: rheumatoid / septic arthritis)

  • NUC (3-phase bone scan):

    • increased flow + increased blood pool + increase in periarticular uptake on delayed images in affected part (60%)

    • diminished flow / delayed uptake (15 20%)

Rx: sympathetic block, - / -adrenergic blocking agents, nonsteroidal antiinflammatory drugs, radiation therapy, hypnosis, acupuncture, acupressure, transcutaneous nerve stimulation, physiotherapy, calcitonin, corticosteroids, early mobilization

Reiter Syndrome

  • = triad of

    • arthritis

    • uveitis

    • urethritis; M:F = 98:2

  • Types:

    • endemic (venereal)

    • epidemic (postdysenteric)

  • history of sexual exposure / diarrhea 3 11 days before onset of urethritis

  • mucocutaneous lesions (keratosis blennorrhagia, balanitis circinata sicca)

  • uveitis, conjunctivitis

  • positive HLA-B27 in 76%

    Location: asymmetric mono- / pauciarticular

  • polyarthritis

  • articular soft-tissue swelling + joint space narrowing in 50% (particularly knees, ankles, feet)

  • widening + inflammation of Achilles + patella tendons

  • fluffy periosteal reaction (DISTINCTIVE) at metatarsal necks, proximal phalanges, calcaneal spur, tibia + fibula at ankle and knee

  • juxtaarticular osteoporosis (rare in acute stage)

  • CHRONIC CHANGES:

    • recurrent joint attacks in a few cases

    • calcaneal spur at insertion of plantar fascia + Achilles tendon

    • periarticular deossification

    • marginal erosions, loss of joint space

    • bilateral sacroiliac changes indistinguishable from ankylosing / psoriatic spondylitis (in 10 40%)

    • paravertebral ossification = isolated floating osteophyte usually in thoracolumbar area

Cx: gastric ulcer + hemorrhage; aortic incompetence; heart block; amyloidosis

Relapsing Polychondritis

  • = rare disorder characterized by generalized recurring inflammation + destruction of cartilage in joints, ears, nose, larynx, airways

    Etiology: acquired metabolic disorder (? abnormal acid mucopolysaccharide metabolism) / hypersensitivity / autoimmune process (antibodies directed against type II collagen)
    Histo: loss of cytoplasm in chondrocytes; plasma cell + lymphocyte infiltration
    Age: 40 60 years (no age predilection)

  • nasal chondritis = saddle-nose deformity

  • bilateral auricular chondritis = swollen + tender ears, cauliflower ears

  • hearing loss (obstruction of external auditory meatus / audiovestibular damage)

  • ocular inflammation

  • cough, hoarseness, dyspnea (collapse of trachea)

  • nonerosive seronegative inflammatory polyarthritis = arthralgia

  • @ Head

    • calcification of pinna of ear

  • @ Chest

    • manubriosternal / costochondral arthropathy (30%)

  • @ Respiratory tract (in up to 70%)

    • ectasia + collapsibility (cartilaginous destruction) of trachea and mainstem bronchi with focal thickening (mucosal edema) + luminal narrowing (fibrosis)

    • bronchiectasis

    • generalized + localized emphysema

  • @ Cardiovascular (in 15 46%)

    • aortic aneurysm (4 10%), mostly in ascending aorta, may be multiple / dissecting

    • aortic / mitral valve insufficiency (8%)

    • systemic vasculitis (13%)

  • @ Bone

    • periarticular osteoporosis

    • erosive changes in carpal bones resembling rheumatoid arthritis

    • soft-tissue swelling around joints + styloid process of ulna

    • erosive irregularities in sacroiliac joints

    • disk space erosion + increased density of articular plates

Rx: corticosteroids, immunosuppression
Prognosis: 74% 5-year survival rate; 55% 10-year survival rate; median survival time of 11 years; airway complications account for >50% of deaths

P.152


Renal osteodystrophy

  • = constellation of musculoskeletal abnormalities that occur with chronic renal failure as a combination of

    • osteomalacia (adults) / rickets (children)

    • 2 HPT with osteitis cystica fibrosa + soft-tissue calcifications

    • osteosclerosis

    • soft-tissue + vascular calcifications

  • Classification:

    • Glomerular form = acquired renal disease: chronic glomerulonephritis (common)

    • Tubular form = congenital renal osteodystrophy:

      • Vitamin D resistant rickets = hypophosphatemic rickets

      • Fanconi syndrome = impaired resorption of glucose, phosphate, amino acids, bicarbonate, uric acid, sodium, water

      • Renal tubular acidosis

  • Pathogenesis:

    • Renal insufficiency causes a decrease in vitamin D conversion into the active 1,25(OH)2D3 (done by 25-OH-D-1-a hydroxylase, which is exclusive to renal tissue mitochondria); vitamin D deficiency slows intestinal calcium absorption; vitamin D resistance predominates and calcium levels stay low (Ca P product remains almost normal secondary to hyperphosphatemia); low calcium levels lead to OSTEOMALACIA; additional factors responsible for osteomalacia are inhibitors to calcification produced in the uremic state, aluminum toxicity, dysfunction of hepatic enzyme system

    • Renal insufficiency with diminished filtration results in phosphate retention; maintenance of Ca P product lowers serum calcium directly, which in turn increases PTH production (2 HPT); 2 HPT predominates associated with mild vitamin D resistance and leads to an increase in Ca P product with SOFT-TISSUE CALCIFICATION in kidney, lung, joints, bursae, blood vessels, heart as well as OSTEITIS FIBROSA

    • Mixture of (a) and (b): increased serum phosphate inhibits vitamin D activation via feedback regulation

  • phosphate retention

  • hypocalcemia

  • OSTEOPENIA (in 0 25 83%)

    • = diminution in number of trabeculae + thickening of stressed trabeculae = increased trabecular pattern

      Cause: combined effect of

      • Osteomalacia (reduced bone mineralization due to acquired insensitivity to vitamin D / antivitamin D factor)

      • Osteitis fibrosa cystica (bone resorption)

      • Osteoporosis (decrease in bone quantity)

        • Contributing factors:

          • chronic metabolic acidosis, poor nutritional status, pre- and posttransplantation azotemia, use of steroids, hyperparathyroidism, low vitamin D levels

            Cx: fracture predisposition (lessened structural strength) with minor trauma / spontaneously; fracture prevalence increases with duration of hemodialysis + remains unchanged after renal transplantation
            Site: vertebral body (3 25%), pubic ramus, rib (5 25%)

    • Milkman fracture / Looser zones (in 1%)

    • metaphyseal fractures

      Prognosis: osteopenia may remain unchanged / worsen after renal transplantation + during hemodialysis

  • RICKETS (children)

    Cause: in CRF normal vessels fail to develop in an orderly way along cartilage columns in zone of provisional calcification; this results in disorganized proliferation of the zone of maturing + hypertrophying cartilage and disturbed endochondral calcification
    Location: most apparent in areas of rapid growth such as knee joints

    • diffuse bone demineralization

    • widening of growth plate

    • irregular zone of provisional calcification

    • metaphyseal cupping + fraying

    • bowing of long bones, scoliosis

    • diffuse concave impression at multiple vertebral end plates, basilar invagination

    • slipped epiphysis (10%): capital femoral, proximal humerus, distal femur, distal radius, heads of metacarpals + metatarsals

    • general delay in bone age

  • SECONDARY HPT (in 6 66%)

    Cause: inability of kidneys to adequately excrete phosphate leads to hyperplasia of parathyroid chief cells (2 HPT); excess PTH affects the development of osteoclasts, osteoblasts, osteocytes

    • hyperphosphatemia

    • hypocalcemia

    • increased PTH levels

    • subperiosteal, cortical, subchondral, trabecular, endosteal, subligamentous bone resorption

    • osteoclastoma = brown tumor = osteitis fibrosa cystica in 1.5 1.7% (due to PTH-stimulated osteoclastic activity; more common in 1 HPT)

    • periosteal new-bone formation (8 25%)

    • chondrocalcinosis (more common in 1 HPT)

  • OSTEOSCLEROSIS (9 34%)

    • One of the most common radiologic manifestations; most commonly with chronic glomerulonephritis; may be the sole manifestation of renal osteodystrophy

    • diffuse chalky density: thoracolumbar spine in 60% (rugger jersey spine); also in pelvis, ribs, long bones, facial bones, base of skull (children)

      Prognosis: may increase / regress after renal transplantation

  • SOFT-TISSUE CALCIFICATIONS

    • = Uremic tumoral calcinosis = secondary tumoral calcinosis = pseudotumor calcinosis

    • Most frequent cause of a periarticular calcified mass!

      • P.153


    • Cause:?

      • metastatic

        • secondary to hyperphosphatemia (solubility product for calcium + phosphate [Ca2+ PO4-2] exceeds 60 75 mg/dL in extracellular fluid), hypercalcemia, alkalosis with precipitation of calcium salts

      • dystrophic

        • secondary to local tissue injury

    • Location:

      • arterial (27 83%):

        • in medial + intimal elastic tissue

          Site: dorsal pedis a., forearm, hand, wrist, leg

        • pipestem appearance without prominent luminal involvement

      • periarticular (0.5 1.2%):

        • multifocal, frequently symmetric, may extend into adjacent joint

        • chalky fluid / pastelike material

        • inflammatory response in surrounding tenosynovial tissue

        • discrete cloudlike dense areas

        • fluid-fluid level in tumoral calcinosis

          Prognosis: often regresses with treatment

      • visceral (79%): heart, lung, stomach, kidney

    • fluffy amorphous tumoral calcification

Rx: 1. Decrease of phosphorus absorption in bowel (in hyperphosphatemia)
  2. Vitamin D3 administration (if vitamin D resistance predominates)
  3. Parathyroidectomy for 3 HPT (= autonomous HPT)

Dialysis-related Disorders

  • Osteomyelitis

  • Osteonecrosis

  • Crystal deposition

  • Destructive spondyloarthropathy

  • Amyloidosis

  • Dialysis cysts

Congenital Renal Osteodystrophy

Vitamin D Resistant Rickets

  • = PHOSPHATE DIABETES = PRIMARY HYPOPHOSPHATEMIA = FAMILIAL HYPOPHOSPHATEMIC RICKETS

  • = rare X-linked dominant disorder of renal tubular reabsorption characterized by

    • impaired resorption of phosphate in proximal renal tubule (due to defect in renal brush-border membrane)

    • inappropriately low synthesis of 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] in renal tubules resulting in decreased intestinal resorption of calcium + phosphate

      Age: <1 year

  • hypophosphatemia + hyperphosphaturia

  • elevated serum alkaline phosphatase

  • normal plasma + urine calcium

  • normal / low serum 1,25(OH)2D3

  • classic rachitic changes

  • skeletal deformity, particularly bowed legs

  • retarded bone age; dwarfism if untreated

  • osteosclerosis / bone thickening (from overabundance of incompletely calcified matrix)

Rx: phosphate infusion + large doses of vitamin D
DDx: vitamin-D deficient and dependent rickets (absence of muscle weakness + seizures + tetany)

Fanconi Syndrome

  • Triad of

    • Hyperphosphaturia

    • Amino aciduria

    • Renal glucosuria (normal blood glucose)

      Etiology: renal tubular defect

  • rickets, osteomalacia, osteitis fibrosa, osteosclerosis

Prognosis: functional renal impairment likely when bone changes occur
Rx: large doses of vitamin D + alkalinization

Renal Tubular Acidosis

  • systemic acidosis, bone lesions

  • rickets, osteomalacia, pseudofractures, nephrocalcinosis, osteitis fibrosa (rare)

    • Lightwood syndrome = salt-losing nephritis (transient self-limited form)

      • NO nephrocalcinosis

    • Butler-Albright syndrome (severe form)

      • nephrocalcinosis

Rheumatoid arthritis

  • = chronic systemic connective tissue disease

  • = type III hypersensitivity = delayed hypersensitivity

  • = immune complex disease (= formation of antigen-antibody complexes with complement fixation) with T-cell mediated autoreactivity against a joint component

    Prevalence: 0.5 1.0% of population
    Cause: genetic predisposition;? reaction to antigen from Epstein-Barr virus / certain strains of E. coli
    Peak age: 45 65 years; M:F = 1:3 if <40 years; M:F = 1:1 if >40 years

  • Pathogenesis:

    • injury to synovial endothelial cells; synovitis with synovial hyperplasia and pannus formation mediated by TNF- (tumor necrosis factor ) and IL-1 (interleukin 1) leads to invasion by local macrophages, fibroblasts, and activated lymphocytes; invasion of articular cartilage + bone by secretion of degrading enzymes (metalloproteinases)

  • Diagnostic Criteria of American Rheumatism Association (at least 4 criteria should be present):

    • morning stiffness for 1 hour before improvement

    • swelling of 3 joints, particularly of wrist, metacarpophalangeal or proximal interphalangeal joints for >6 weeks

    • symmetric swelling

    • typical radiographic changes

    • subcutaneous rheumatoid nodules

    • positive test for rheumatoid factor

  • morning stiffness

  • fatigue, weight loss, anemia

  • carpal tunnel syndrome

    • P.154


  • rheumatoid factor (positive in 85 94%) = IgM-antibody

    • = agglutination of sensitized sheep RBCs closely correlating with disease severity

      • false positive: normal (5%), asbestos workers with fibrosing alveolitis (25%), viral / bacterial / parasitic infection, other inflammatory diseases

  • antinuclear antibodies (positive in many)

  • LE cells (positive in some)

  • positive latex flocculation test

  • hormonal influence:

    • decrease in activity during pregnancy

    • men with RA have low testosterone levels

      Location: bilateral symmetric involvement of >3 diarthrodial joints (polyarthritis)
        Symmetric arthritis of multiple small hand joints in >60% of patients at initial presentation

  • EARLY SIGNS:

    • MR & US (methods of choice):

      • synovial hyperemia (in acute disease + exacerbation of chronic disease)

      • synovial swelling (edema + cellular infiltrates)

      • pannus = tumorlike focal proliferation of inflammatory tissue with destruction of cartilage and bone

      • pre-erosive subcortical cysts

      • joint effusion

      • bone marrow edema

    • Radiography (indirect & nonspecific):

      • fusiform periarticular soft-tissue swelling (result of effusion)

      • paraarticular osteoporosis (inactivity due to pain + local inflammatory hyperthermia)

      • translucent subchondral end plate

      • widened joint space (synovial swelling + fluid)

      • effacement of fat pads

      • subcortical synovial cyst

      • erosion (up to 47% within 1st year after onset) initially at bare area (= site of attachment of internal synovial layer of joint capsule to bone) due to lack of protective cartilage layer

  • LATE SIGNS:

    • concentric joint space narrowing (due to destruction of cartilage, formation of scar tissue, fibrosis)

    • subluxation (due to laxity of capsule + ligaments from inflammatory destruction / due to capsular shrinkage from fibrosis + scar formation):

      • mallet finger = droopy distal phalanx due to disrupted extensor tendon insertion site

      • swan-neck deformity = hyperextension at PIP + flexion at DIP

      • boutonni re deformity = flexion at PIP + hyperextension at DIP

      • hitchhiker deformity = flexion at MCP + hyperextension at DIP

    • dislocation

    • marked destruction + fractures of bone ends:

      • intraarticular loose bodies

      • rice bodies = subset of loose bodies resembling polished rice (made of sloughed fibrinogen-coated infarcted synovial tissue / precipitate of fibrin + fibronectin / core of mononuclear cells, blood cells and amorphous material)

    • bony ankylosis

  • @ Hand & wrist (typical)

    • Target areas:

      • all five MCP, PIP, interphalangeal joint of thumb, all wrist compartments (especially radiocarpal, inferior radioulnar, pisiform-triquetral joints); earliest changes seen in MCP 2 + 3, PIP 3

    • marginal + central bone erosions (less common in large joints); site of first erosion is classically base of proximal phalanx of 4th finger

    • changes in the ulnar styloid + distal radioulnar joint (early sign)

    • flexion + extension contractures with ulnar subluxation + dislocation

  • @ Cervical spine

    • erosions of odontoid process (1) between anterior arch of atlas + dens, (2) between transverse ligament of atlas + dens, (3) at tip of odontoid process

    • anterior atlantoaxial subluxation (in >6%): >2.5 mm in adults, >4.5 mm in children during neck flexion

    • cranial settling = odontoid process projects into skull base due to significant disease of atlanto-occipital and atlantoaxial joints

    • lateral head tilt = lateral subluxation = asymmetry between odontoid process + lateral masses of atlas

    • stepladder appearance of cervical spine due to subaxial subluxations + absence of osteophytosis:

      • destruction + narrowing of disk spaces

      • irregular vertebral body outlines

      • erosion + destruction of zygapophyseal joints

      • resorption of spinous processes

    • osteoporosis

      Cx: spinal cord compression

  • @ Ribs

    • erosion of superior margins of posterior portions of ribs 3 5

  • @ Shoulder

    • symmetric loss of glenohumeral joint space:

      • marginal erosions at superolateral aspect of humeral head

      • osteoporosis

      • elevation of humeral heads = narrowing of acromiohumeral distance (2 to tear / atrophy of rotator cuff)

        Subluxations in rheumatoid arthritis

      • P.155


    • widened acromioclavicular joint:

      • erosions at acromial + clavicular end

      • tapered margins of distal clavicle

    • scalloped erosion on undersurface of distal clavicle opposite the coracoid process (attachment of coracoclavicular ligament)

  • @ Sacroiliac joint (rarely affected)

    • typically asymmetric unilateral distribution

    • shallow erosions + mild sclerosis

    • rare ankylosis

  • @ Hip (rarely affected)

    • often appears normal during early disease process

    • pannus formation (MR imaging)

    • symmetric loss of joint space with axial migration of femoral head

    • marginal + central erosions, cysts, localized sclerosis

    • decompression of joint effusion into iliopsoas bursa through weak anterior capsule displacing muscle + vasculature

    • rupture of gluteal tendon

    • protrusio acetabuli (from osteoporosis)

  • @ Knee

    Location: medial + lateral femorotibial compartments; bilateral symmetric

  • diffuse loss of joint space

  • osteoporosis

  • superficial + deep marginal + central erosions

  • subchondral sclerosis (especially in tibia)

  • synovial herniation + cysts (eg, popliteal cyst)

  • varus / valgus angulation (due to crumbling of osteoporotic bone of tibia + ligamentous abnormalities)

  • @ Foot (typical)

    • Target areas:

      • medial aspect of MT heads (2,3,4), medial + lateral aspect of MT5 (earliest sign); interphalangeal joints of foot (esp. great toe); midfoot joints; talonavicular, subtalar, tarsometatarsal joints; bilateral + symmetric

    • sinus tarsi syndrome = compression of tibial nerve

    • calcaneal plantar spur

    • retrocalcaneal bursitis

      DDx: SLE, seronegative spondyloarthropathies (proliferative changes at bone + tendinous insertion sites, bony ankylosis)

  • EXTRA-ARTICULAR MANIFESTATIONS (76%)

    • Felty syndrome (<1%)

      • = rheumatoid arthritis (present for >10 years) + splenomegaly + neutropenia

        Age: 40 70 years; F > M; rare in Blacks

      • rapid weight loss

      • therapy refractory leg ulcers

      • brown pigmentation over exposed surfaces of extremities

    • Sj gren syndrome (15%)

      • = keratoconjunctivitis + xerostomia + rheumatoid arthritis

    • Pulmonary manifestations

      • pleural effusion, mostly unilateral, without change for months, usually not associated with parenchymal disease

      • interstitial fibrosis with lower lobe predominance

        Prevalence: 2 9% of rheumatoid patients

      • rheumatoid nodules (30%): well-circumscribed, peripheral, with frequent cavitation

      • Caplan syndrome (= hyperimmune reactivity to silica inhalation with rapidly developing multiple pulmonary nodules)

      • pulmonary hypertension secondary to arteritis

    • Subcutaneous nodules

      • (in 5 35% with active arthritis) over extensor surfaces of forearm + other pressure points (eg, olecranon) without calcifications (DDx to gout)

    • Cardiovascular involvement

      • Pericarditis (20 50%)

      • Myocarditis (arrhythmia, heart block)

      • Aortitis (5%) of ascending aorta aortic valve insufficiency

    • Rheumatoid vasculitis

      • = leukocytoclastic lesion of small venules mimicking periarteritis nodosa

      • polyneuropathy, cutaneous ulceration, gangrene, polymyopathy, myocardial / visceral infarction

    • Neurologic sequelae

      • Distal neuropathy (related to vasculitis)

      • Nerve entrapment (atlantoaxial subluxation, carpal tunnel syndrome, Baker cyst)

    • Lymphadenopathy (up to 25%)

      • splenomegaly (1 5%)

Cystic Rheumatoid Arthritis

  • = intraosseous cystic lesions as dominant feature

    Pathogenesis: increased pressure in synovial space from joint effusion decompresses through microfractures of weakened marginal cortex into subarticular bone

  • Increase in size + extent of cysts correlates with increased level of activity + absence of synovial cysts

    Age: as above; M:F = 1:1

  • seronegative in 50%

  • juxtaarticular subcortical lytic lesions with well-defined sclerotic margins

  • relative lack of cartilage loss, osteoporosis, joint disruption

DDx: gout (presence of urate crystals), pigmented villonodular synovitis (monoarticular)

Juvenile Rheumatoid Arthritis

  • = rheumatoid arthritis in patients <16 years of age; M < F

  • morning stiffness, arthralgia

  • subcutaneous nodules (10%)

  • skin rash (50%)

  • fever, lymphadenopathy

    Location: early involvement of large joints (hips, knees, ankles, wrists, elbows); later of hands + feet

  • radiologic signs similar to rheumatoid arthritis (except for involvement of large joints first, late onset of bony changes, more ankylosis, wide metaphyses)

  • periarticular soft-tissue swelling

  • thinning of joint cartilage

  • large cystlike lesions removed from articular surface (invasion of bone by inflammatory pannus); rare in children

  • articular erosions at ligamentous + tendinous insertion sites

  • joint destruction may resemble neuropathic joints

    • P.156


  • juxtaarticular osteoporosis

  • balloon epiphyses + gracile bones (epiphyseal overgrowth + early fusion with bone shortening secondary to hyperemia)

  • @ Hand / foot

    • rectangular phalanges (periostitis + cortical thickening)

    • ankylosis in carpal joints

  • @ Axial skeleton

    Location: predominantly upper cervical spine

    • ankylosis of cervical spine (apophyseal joints), sacroiliac joints

    • decreased size of vertebral bodies + atrophic intervertebral disks

    • subluxation of atlantoaxial joint (66%)

    • thoracic spinal compression fractures

  • @ Chest

    • ribbon ribs

    • pleural + pericardial effusions

    • interstitial pulmonary lesions (simulating scleroderma, dermatomyositis)

    • solitary pulmonary nodules, may cavitate

      Prognosis: complete recovery (30%); secondary amyloidosis

  • Clinical classification:

    • Juvenile-onset adult type (10%)

      • IgM RA factor positive; age 8 9; poor prognosis

      • erosive changes; profuse periosteal reaction; hip disease with protrusio

    • Polyarthritis of the ankylosing spondylitic type

      • iridocyclitis; boys age 9 11 years

      • peripheral arthritis; fusion of greater trochanter; complete fusion of both hips; heel spur

    • Still disease

      • systemic

      • polyarticular

      • pauciarticular + iridocyclitis (30%)

      • fever, rash, lymphadenopathy, hepatosplenomegaly; pericarditis, dwarfism

      • fatal kidney disease in 20%

        Age: 2 4 and 8 11 years of age; M < F
        Location: involvement of carpometacarpal joints ( squashed carpi in adulthood), hind foot, hip (40 50%)

      • periosteal reaction of phalanges; broadening of bones; accelerated bone maturation + early fusion (stunting of growth)

Rickets

  • = osteomalacia during enchondral bone growth

    Age: 4 18 months
    Histo: zone of maturation has an increase in number of maturing cartilage cells with loss of normal columnar arrangement; zone of preparatory calcification does not form; failure of osteoid mineralization also in shafts so that osteoid production elevates periosteum

  • irritability, bone pain, tenderness

  • craniotabes

  • rachitic rosary

  • bowed legs

  • delayed dentition

  • swelling of wrists + ankles

    Location: metaphyses of long bones subjected to stress are particularly involved (wrists, ankles, knees); costochondral junction of ribs

  • poorly mineralized irregular epiphyseal centers with delayed appearance

  • axial widening of growth plate = increase in distance between end of shaft and epiphyseal center due to increased osteoid production (earliest changes)

  • cupping + fraying of metaphysis with threadlike shadows into epiphyseal cartilage (weight-bearing bones)

  • cortical spurs projecting at right angles to metaphysis

  • coarse trabeculation (NO ground-glass pattern as in scurvy)

  • periosteal reaction may be present

  • deformities common (bowing of soft diaphysis, molding of epiphysis, fractures)

  • bowing of long bones

  • frontal bossing

    mnemonic: RICKETS

    • Reaction of periosteum may occur

    • Indistinct cortex

    • Coarse trabeculation

    • Knees + wrists + ankles mainly affected

    • Epiphyseal plates widened + irregular

    • Tremendous metaphysis (fraying, splaying, cupping)

    • Spur (metaphyseal)

Cx: stress fracture, bowing deformity

Causes of Rickets

  • ABNORMALITY IN VITAMIN D METABOLISM associated with reactive hyperparathyroidism

    • Vitamin D deficiency (most common cause)

      • Dietary lack of vitamin D = famine osteomalacia = nutritional lack of vitamin precursors (vegetarian diet, prolonged total breast feeding without vitamin D supplementation)

      • Lack of sunshine exposure

        • eg, residence in high latitudes, clothing covering skin, sunshine avoidance for religious / cultural reasons, heavy skin pigmentation

      • Malabsorption of vitamin D

        • = gastroenterogenous rickets due to

          • Pancreatitis + biliary tract disease

          • Steatorrhea, celiac disease, postgastrectomy

          • Inflammatory bowel disease

    • Defective conversion of vitamin D to 25-OH-cholecalciferol (vitamin D3) in liver

      • Liver disease

      • Anticonvulsant drug therapy (= induction of hepatic enzymes that accelerate degradation of biologically active vitamin D metabolites)

    • Defective conversion of 25-OH-D3 to 1,25-OH-D3 in kidney

      • Chronic renal failure = renal osteodystrophy

      • Vitamin D dependent rickets = autosomal recessive enzyme defect of 1-OHase

  • ABNORMALITY IN PHOSPHATE METABOLISM

    • not associated with hyperparathyroidism secondary to normal serum calcium

      P.157


      • Phosphate deficiency

        • Intestinal malabsorption of phosphates

        • Ingestion of aluminum salts [Al(OH)2] forming insoluble complexes with phosphate

        • Low phosphate feeding in prematurely born infants

        • Severe malabsorption state

        • Parenteral hyperalimentation

      • Disorders of renal tubular reabsorption of phosphate

        • Renal tubular acidosis (renal loss of alkali)

        • deToni-Debr -Fanconi syndrome = hypophosphatemia, glucosuria, aminoaciduria

        • Vitamin D resistant rickets

        • Cystinosis

        • Tyrosinosis

        • Lowe syndrome

        • Ifosfamide nephrotoxicity (for the treatment of rhabdomyosarcoma, Wilms tumor)

      • Hypophosphatemia with nonendocrine tumors

        • = Oncogenic rickets = elaboration of humeral substance which inhibits tubular reabsorption of phosphates (paraneoplastic phenomenon)

          • Nonossifying fibroma

          • Sclerosing hemangioma

          • Hemangiopericytoma

          • Ossifying mesenchymal tumor

      • Hypophosphatasia

  • CALCIUM DEFICIENCY

    • Dietary rickets = milk-free diet (extremely rare)

    • Malabsorption

    • Consumption of substances forming chelates with calcium

Classification of Rickets

  • Primary vitamin D deficiency rickets

  • Gastrointestinal malabsorption

    • Partial gastrectomy

    • Small intestinal disease: gluten-sensitive enteropathy / regional enteritis

    • Hepatobiliary disease: biliary atresia / chronic biliary obstruction / biliary cirrhosis resulting in failure of the emulsifying action of bile salts (fat-soluble vitamin) or failure of conversion

    • Pancreatic disease: chronic pancreatitis

  • Primary hypophosphatemia; vitamin D deficiency rickets

  • Renal disease

    • Chronic renal failure

    • Renal tubular disorders: renal tubular acidosis

    • Multiple renal defects

  • Hypophosphatasia + pseudohypophosphatasia

  • Fibrogenesis imperfecta osseum

  • Axial osteomalacia

  • Miscellaneous:

    • Hypoparathyroidism, hyperparathyroidism, thyrotoxicosis, osteoporosis, Paget disease, fluoride ingestion, ureterosigmoidostomy, neurofibromatosis, osteopetrosis, macroglobulinemia, malignancy

Rotator Cuff Lesions

Subacromial Pain Syndrome

  • Impingement syndrome

  • Rotator cuff tendinitis

  • Degeneration without impingement

  • Shoulder instability with secondary impingement

  • Instability without impingement

Impingement Syndrome

  • = clinical diagnosis consisting of lateral shoulder pain with abduction and forward flexion; NOT radiographic diagnosis

    Cause: inadequate space for the normal motion of rotator cuff
    Age: lifelong process; 1st stage <25 years; 2nd stage 25 40 years; complete rotator cuff tear >40 years

  • Pathophysiology:

    • movement of humerus impinges rotator cuff tendons against coracoacromial arch resulting in microtrauma, which causes inflammation of subacromial bursa

    • (= fibrous thickening of subacromial bursa) / rotator cuff (critical zone of rotator cuff = supraspinatus tendon 2 cm from its attachment to humerus)

    • Impingement pathophysiology may be secondary to primary instability!

  • Impingement anatomy:

    • narrowing of subacromial space secondary to

      • (1) acquired

        • degenerative subacromial osteophyte / enthesophyte from

          • bony outgrowth along coracoacromial ligament (= subacromial spur)

          • acromioclavicular joint hypertrophy in osteoarthrosis

        • hypertrophy of coracoacromial ligament

        • primary bursitis in rheumatoid arthritis

        • swollen supraspinatus tendon calcific tendinosis impinging upon coracoacromial arch

      • congenital

        • subacromial hook of anterior acromion (= subacromial spur)

        • increased curvature of acromion

        • os acromiale

  • Impingement syndrome may exist without impingement anatomy!

  • painful arc of motion

  • night pain

  • X-ray (supraspinatus outlet + caudal tilt view):

    • anterior tilt / low position of acromion

    • anterior subacromial spur (= enthesophyte) at insertion site of coracoacromial ligament

  • MR (can identify the anatomy predisposing to impingement):

    • unstable os acriomale pulled downward by deltoid muscle during abduction

    • thickening of coracoacromial ligament

    • acromioclavicular joint osteoarthritis bone spurs

  • US:

    • bunching of subdeltoid bursa during abduction of arm

    • US can direct steroid injection into bursa

P.158


Cx: (1) partial / complete tear (may be precipitated by acute traumatic event on preexisting degenerative changes; common cause of rotator cuff tears)
  (2) cuff tendinitis / degenerative tendinosis
Dx: Lidocaine impingement test (= subacromial lidocaine injection relieves pain)
Rx: acromioplasty (= removal of a portion of the acromion), removal of subacromial osteophytes, removal / lysis / d bridement of coracoacromial ligament, resection of distal clavicle, removal of acromioclavicular joint osteophytes

Glenohumeral Instability

  • Glenohumeral stability is dependent on a functional anatomic unit (= anterior capsular mechanism) formed by: glenoid labrum, joint capsule, superior + middle + anteroinferior + posteroinferior glenohumeral ligaments, coracohumeral ligament, subscapularis tendon, rotator cuff

    Age: <35 years
    Frequency: acute, recurrent, fixed
    Cause: traumatic, microtraumatic, atraumatic
    Direction: anterior > multidirectional > inferior > posterior

  • Type of lesions:

    • labral abnormalities (compression, avulsion, shearing), capsular / ligamentous tear / avulsion

  • Associated lesions:

    • Hill-Sachs fracture, trough line fracture, glenoid fracture, labral cyst

    • Normal clefts may exist within labrum!

  • False positive for labral separation:

    • Articular cartilage deep to labrum

    • Glenohumeral ligaments passing adjacent to labrum

Rotator Cuff Tear

  • Etiology:

    • Attritional change + tendon degeneration due to aging, repeated microtrauma as a result of impingement between humeral head + coracoacromial arch, overuse of shoulder from professional / athletic activities

    • Acute trauma (rare)

      Age: most commonly >50 years; young athletic patient may have rim-rent tear (= avulsion of attachment at greater tuberosity
      Location: critical zone of anterior supraspinatus tendon 1 cm medial to tendon attachment (area of relative hypovascularity)

    • Classification:

      • EXTENT OF TEAR

        • incomplete rupture = partial tear involves either bursal or synovial surface or remains intratendinous

          • fluid-filled defect not extending across the entire tendon width

          • disruption of the superior / inferior tendon fibers only

        • complete rupture = full-thickness tear bridging subacromial bursa and glenohumeral joint

          • pure transverse tear

          • pure vertical / longitudinal tear

          • tear with retraction of tendon edges

          • global tear = massive tear / avulsion of cuff involving more than one of the tendons

      • TOPOGRAPHY OF TEAR

        • extent in frontal plane: nondisplaced, minimally displaced, dramatically displaced

        • extent in anterior direction: supraspinatus tendon + coracohumeral ligament + subscapularis tendon

        • extent in posterior direction: supraspinatus tendon + infraspinatus tendon + teres minor tendon

    • Assessment:

      • Size of tear

      • Amount of myotendinous retracion

      • Amount of surrounding tendinopathy

      • Muscle atrophy (decreased bulk, fatty infiltration) as strongest prognosticator of surgical outcome

        • Infraspinatus muscle atrophy is irreversible!

    • X-ray (late findings):

      • superior migration of humeral head

      • remodeling of acromial undersurface

      • Osseous changes in greater tuberosity do not correlate with cuff disease!

    • Arthrography (71 100% sensitive, 71 100% specific for combined full + partial thickness tears):

      • opacification of subacromial-subdeltoid bursa

      • contrast enters substance of rotator cuff tendons

    • MR (41 100% sensitive and 79 100% specific for combined full + partial thickness tears):

      • discontinuity of cuff with retraction of musculotendinous junction

      • focal / generalized intense / markedly increased signal intensity on T2WI (= fluid within cuff defect) in <50%

      • fluid within subacromial-subdeltoid bursa (MOST SENSITIVE)

      • low / moderate signal intensity on T2WI (= severely degenerated tendon, intact bursal / synovial surface, granulation / scar tissue filling the region of torn tendinous fibers)

      • cuff defect with contour irregularity

      • abrupt change in the signal character at boundary of the lesion

      • supraspinatus muscle atrophy (MOST SPECIFIC)

      • Pitfalls:

        • hyperintense focus in distal supraspinatus tendon

        • gray signal isointense to muscle on all pulse sequences

          • partial volume averaging with superior + lateral infraspinatus tendon

          • vascular watershed area

          • magic angle effect = orientation of collagen fibers at 55 relative to main magnetic field

        • hyperintense focus within rotator cuff on T2WI

          • partial volume averaging with fluid in biceps tendon sheath / subscapularis bursa

          • partial volume averaging with fat of peribursal fat

          • motion artifacts: respiration, vascular pulsation, patient movement

        • fatty atrophy of muscle

          • impingement of axillary / suprascapular nn. = quadrilateral space syndrome

            DDx: (1) Partial-thickness tear with diffuse less-than-fluid intensity on T2WI
              (2) Tendon degeneration (tendonopathy)
              (3) Tendinitis
              (4) Full-thickness tear containing granulation tissue

      • P.159


    • US (scans in hyperextended position, 75 100% sensitive, 43 97% specific, 65 95% negative predictive value, 55 75% positive predictive value):

      • nonvisualization of rotator cuff (large tear), most reliable sign:

        • deltoid muscle directly on top of humeral head

        • defect filled with hypoechoic thickened bursa + fat (with hypervascularity on color Doppler) between deltoid and humeral head

      • focal nonvisualization of rotator cuff, reliable sign:

        • naked tuberosity sign = retracted tendon leaves a bare area of bone

        • folding of bursal + peribursal fat tissue into focal defect

      • discontinuity of rotator cuff filled with joint fluid / hypoechoic reactive tissue

      • abrupt + sharply demarcated focal thinning

      • small comma-shaped area of hyperechogenicity (small tear filled with granulation tissue / hypertrophied synovium)

False negative: longitudinal tear, partial tear
False positive: intraarticular biceps tendon, soft-tissue calcification, small scar / fibrous tissue

Subacromial-Subdeltoid Bursitis

  • common finding in rotator cuff tears

  • peribursal fat totally / partially obliterated + replaced by low-signal-intensity tissue on all pulse sequences

  • fluid accumulation within bursa

Supraspinatus Tendinopathy / Tendinosis

  • = chronic tendon degeneration with disorganized repair

    Cause: impingement, acute / chronic stress
    Histo: mucinous + myxoid degeneration

  • increase in signal intensity in tendon on proton-density images without disruption of tendon

  • tendinous enlargement + inhomogeneous signal pattern

  • fibers on superior + inferior tendon surface remain visible and contiguous

Cx: main risk factor for subsequent rotator cuff tear (not impingement)
DDx: supraspinatus tear (tendon has fluid intensity

Rubella

  • = CONGENITAL RUBELLA = GERMAN MEASLES

    Incidence: endemic rate of 0.1%
    Age: infants (in utero transmission)

  • neonatal dwarfism (intrauterine growth retardation)

  • failure to thrive

  • retinopathy, cataracts, glaucoma, microphthalmia

  • deafness

  • mental deficiency with encephalitis + microcephaly

  • thrombocytopenic purpura, petechiae, anemia

  • celery-stalk sign (50%) = metaphyseal irregular margins + coarsened trabeculae extending longitudinally from epiphysis; distal end of femur > proximal end of tibia, humerus

  • no periosteal reaction

  • hepatosplenomegaly + adenopathy

  • pneumonitis

  • @ Cardiovascular:

    • congenital heart disease (PDA, VSD)

    • peripheral pulmonary artery stenosis

    • necrosis of myocardium

  • @ CNS

    • punctate / nodular calcifications

    • porencephalic cysts

    • occasionally microcephaly

Prognosis: osseous manifestations disappear in 1 3 months; severe congenital defects from infection during first trimester
DDx: (1) CMV
  (2) Congenital syphilis (diaphysitis + epiphysitis)
  (3) Toxoplasmosis

Rubinstein-Taybi Syndrome

  • = BROAD THUMB SYNDROME

  • = rare sporadic syndrome without known chromosomal / biochemical markers; M:F = 1:1

  • small stature

  • mental, motor, language retardation

  • @ Characteristic facies

    • beaked / straight nose low nasal septum

    • antimongoloid slant of palpebral fissures

    • epicanthic folds

    • broad fleshy nasal bridge

    • high-arched palate

    • dental abnormalities

  • @ Ophthalmologic findings

    • strabismus, ptosis, refractive errors

  • @ Cutaneous findings

    • keloids, hirsutism, simian crease

    • flat capillary hemangioma on forehead / neck

  • @ Musculoskeletal findings

    • short broad spatulate terminal phalanges of thumb and great toe angulation deformity (MOST CONSISTENT + CHARACTERISTIC FINDING)

    • radial angulation of distal phalanx (50%) caused by trapezoid / delta shape of proximal phalanx

    • tufted mushroom-shaped fingers + webbing

    • thin tubular bones of hand + feet

    • club feet

    • skeletal maturation retardation

    • dysplastic ribs

    • spina bifida occulta

    • scoliosis

    • flat acetabular angle + flaring of ilia

  • @ Genitourinary tract anomalies

    • bilateral renal duplication

    • renal agenesis

    • bifid ureter

    • incomplete / delayed descent of testes

  • @ Cardiovascular abnormalities

    • atrial septal defect

    • patent ductus arteriosus

    • coarctation of aorta

    • valvular aortic stenosis

      • P.160


    • pulmonic stenosis

  • OB-US:

    • decreased head circumference

    • small for gestational age

Cx in infancy: obstipation, feeding problems, recurrent upper respiratory infection

Sapho Syndrome

  • = Synovitis, Acne, Palmoplantar pustulosis, Hyperostosis, Osteitis

  • = PUSTULOTIC ARTHROSTEITIS = STERNOCLAVICULAR HYPEROSTOSIS

  • = association between rheumatologic and cutaneous lesions (= seronegative spondyloarthropathy)

  • Delay of several years can separate osseous from cutaneous lesions!

    Etiology: ? variant of psoriasis
    Age: young to middle-aged adults; M:F = 1:1

  • palmoplantar pustulosis (52%) = chronic eruption of yellowish intradermal sterile pustules on palms + soles

  • severe acne (15%) = acne fulminans, acne conglobata

  • pain, soft-tissue swelling, limitation of motion at skeletal site of involvement

  • @ Sternoclavicular joint (70 90%)

    Site: insertion of costoclavicular ligament, clavicles, manubrium sterni

    • osteolysis at beginning of disease

    • hyperostosis + osteosclerosis

    • arthritis + ankylosis of sternoclavicular joint

  • @ Axial skeleton (33%)

    • osteosclerosis of one / more vertebral bodies

    • disk space narrowing + endplate erosion

    • paravertebral ossifications (mimicking marginal / nonmarginal syndesmophytes / massive bridging)

    • unilateral sacroiliitis + associated osteosclerosis of adjacent iliac bone

  • @ Appendicular skeleton (30%)

    Location: distal femur, proximal tibia, fibula, humerus, radius, ulna
    Site: metaphysis

    • osteosclerosis / osteolysis + periosteal new bone formation with aggressive appearance

  • @ Joints

    Location: knee, hip, ankle, DIP of hand

    • synovial inflammation with juxtaarticular osteoporosis (early)

    • joint narrowing, marginal erosion, hyperostosis, enthesopathy (later)

Prognosis: chronic course with unpredictable exacerbations + remissions
Rx: nonsteroidal antiinflammatory drugs, corticosteroids, analgesics, cyclosporine
DDx: infectious osteomyelitis / spondylitis, osteosarcoma, Ewing sarcoma, metastasis, Paget disease, aseptic necrosis of clavicle

Sarcoidosis

  • Osseous involvement in 6 15 20%

  • unimpaired joint function, joints are rarely involved

    Location: small bones of hands + feet (middle + distal phalanges)

  • reticulated lacelike trabecular pattern in metaphyseal ends of middle + distal phalanges, metacarpals, metatarsals

  • well-defined cystlike lesions of varying size

  • neuropathy-like destruction of terminal phalanges (DDx: scleroderma)

  • phalangeal endosteal sclerosis + periosteal new bone (infrequent)

  • vertebral involvement unusual: destructive lesions with sclerotic margin

  • diffuse sclerosis of multiple vertebral bodies

  • paravertebral soft-tissue mass (DDx: indistinguishable from tuberculosis)

  • osteolytic changes in skull

Scurvy

  • = BARLOW DISEASE = HYPOVITAMNOSIS C

  • = vitamin C (= ascorbic acid) deficiency with defective osteogenesis from abnormal osteoblast function

Infantile Scurvy

Age: 6 9 months (maternal vitamin C protects for first 6 months)
Predisposed: feeding with pasteurized / boiled milk
Pathogenesis: abnormal collagen formation

  • irritability

  • tenderness + weakness of lower limbs

  • scorbutic rosary of ribs

  • bleeding of gums (teething)

  • legs drawn up + widely spread = pseudoparalysis

    Location: distal femur (esp. medial side), proximal and distal tibia + fibula, distal radius + ulna, proximal humerus, sternal end of ribs

  • ground-glass osteoporosis (CHARACTERISTIC)

  • cortical thinning

  • soft-tissue edema (rare)

  • @ Metaphysis

    • white line of Fr nkel = metaphyseal zone of preparatory calcification (DDx: lead / phosphorus poisoning, bismuth treatment, healing rickets)

    • Tr mmerfeld zone = radiolucent zone on shaft side of Fr nkel's white line (site of subepiphyseal infraction)

    • Pelkan spurs = metaphyseal spurs projecting at right angles to shaft axis

    • Parke corner sign = subepiphyseal infraction / comminution resulting in mushrooming / cupping of epiphysis (DDx: syphilis, rickets)

  • @ Epiphysis

    • Wimberger ring = sclerotic ring around low-density epiphysis (due to osteopenia of epiphysis)

  • @ Diaphysis

    • subperiosteal hematoma with calcification of elevated periosteum (sure sign of healing)

  • @ Teeth

    • cyst formation + hemorrhage in enamel

DDx: TORCH infections, leukemia, neuroblastoma

Adult Scurvy

Incidence: rare

P.161


  • hemarthroses + bleeding at synchondroses

Septic Arthritis

N.B.: MEDICAL EMERGENCY = immediate treatment necessary to prevent permanent joint damage!

Organism:

  • most often due to Staphylococcus aureus;

  • gonorrhea (multifocal septic arthritis in young adults; indistinguishable from tuberculous arthritis, but more rapid);

  • brucellar arthritis (indistinguishable from tuberculosis, slow infection);

  • Salmonella (commonly associated with sickle cell disease / Gaucher disease)

    (a) neonates, infants: group D streptococcus
    (b) <4 years of age: Hemophilus influenzae, Strepto-coccus pyogenes, S. aureus
    (c) >4 years of age: S. aureus
    (d) >10 years of age: S. aureus, Neisseria gonorrheae
    (e) adults: S. aureus

Pathophysiology:

  • lytic enzymes in purulent articular fluid destroy articular + epiphyseal cartilages

  • pus increases intraarticular pressure and compromises blood flow to epiphysis resulting in osteonecrosis

Mode of infection:

  • hematogenous spread (most common; IV drug abuser, immunocompromised patient):

    • hip, knee in children

    • the five S joints in adults:

      • Shoulder (AC joint)

      • Sternoclavicular joint

      • Spine

      • SI joint

      • Symphysis pubis

  • contiguous spread from focus of osteomyelitis

    • metaphyseal focus: hip, elbow, shoulder, ankle have intraarticular metaphyses (children)

    • epiphyseal focus: growth plate perforated by vascular channels in children <1 year of age

  • direct inoculation of joint from penetrating wound:

    • small joints of hand + feet; unusual organisms like Pseudomonas + Klebsiella

Age: most prevalent in the young
Location: lower extremity (75%) with hip + knee in 90%

  • pain, limp, pseudoparalysis

  • warmth, swelling

  • septic clinical picture

  • bacteremia, leukocytosis

ACUTE SIGNS:

  • initial radiographs frequently normal

  • soft-tissue swelling (first sign secondary to local hyperemia + edema)

  • joint distension (effusion) subluxation of hip and humerus in children (early)

  • joint space narrowing = rapid development of destruction of articular cartilage (not in tuberculous arthritis)

  • rapid periarticular osteoporosis

US:

  • detection + follow-up of hip effusion

NUC:

  • increased activity in joint + adjacent osteomyelitis

  • occasionally decreased activity simulating avascular necrosis (2 to joint effusion, vascular spasm, vascular compression)

MR:

  • hypointense signal in bone marrow on T1WI

  • enhancement of abnormal bone marrow on fat-suppressed T1WI

  • hyperintense signal in bone marrow on fat-suppressed T2WI

SUBACUTE SIGNS after 8 10 days:

  • small marginal + central erosions in articular cortex / loss of entire cortical outline (marginal erosions in tuberculosis)

  • reactive bone sclerosis in underlying bone

  • subchondral bone destruction (by synovial proliferation)

  • defective reparation / ankylosis (if entire cartilage is destroyed)

  • local bone atrophy (immobility)

  • metaphyseal bone destruction (if osteomyelitis is source of septic joint)

Dx: (1) prompt arthrocentesis:
    turbid / frankly purulent synovial fluid:
    fluid WBC >20,000/mm3 with predominance of PMNs:
    positive result of Gram stain
(2) blood culture
Cx: (1) bone growth disturbance (lengthening, shortening, angulation)
(2) chronic degenerative arthritis
(3) ankylosis
(4) osteonecrosis = avascular necrosis

Shin Splints

  • = SHIN SORENESS = MEDIAL TIBIAL STRESS SYNDROME

    • = SOLEUS SYNDROME

  • = nonspecific term describing exertional lower leg pain

    Incidence: 75% of exertional leg pain
    Cause: ? atypical stress fracture, traction periostitis, compartment syndrome

  • diffuse tenderness along posteromedial tibia in its middle to distal aspect

    Location: posterior / posteromedial tibial cortex

  • Plain radiographs:

    • normal / longitudinal periosteal new bone

  • Bone scintigraphy:

    • normal radionuclide angiogram + blood-pool phase (DDx to stress fracture)

    • linear longitudinal uptake on delayed images

  • MR:

    • marrow edema / hemorrhage

    • periosteal fluid

Short Rib Polydactyly Syndrome

  • = group of autosomal recessive disorders characterized by short limb dysplasia, constricted thorax, postaxial polydactyly (on ulnar / fibular side)

    P.162


    TYPE I = SALDINO-NOONAN SYNDROME
    TYPE II = MAJEWSKI TYPE
    TYPE III = NAUMOFF TYPE
    TYPE IV = BEEMER

  • severe micromelia

  • pointed femurs at both ends (type I); widened metaphyses (type III)

  • narrow thorax

  • extremely short horizontally oriented ribs

  • distorted underossified vertebral bodies + incomplete coronal clefts

  • polydactyly

  • cleft lip / palate

    Prognosis: uniformly lethal

Sickle cell disease

  • Abnormal hemoglobins:

    HbS = DNA mutation substituting glutamic acid in position 6 on -chain with valine
    HbC = DNA mutation substituting glutamic acid in position 6 on -chain with lysine

    • homozygous = HbSS = sickle cell anemia

    • heterozygous = HbSA = sickling trait but no anemia

    • heterozygous variants:

      • HbSC (less severe form)

      • HbS -thalassemia anemia (seen occasionally)

    Incidence: 8 13% of American Blacks carry sickling factor (HbS); 1:40 with sickle cell trait will manifest sickle cell anemia (HbSS); 1:120 with sickle cell trait will manifest HbSC disease

  • Pathogenesis:

    • altered shape + plasticity of RBCs under lowered oxygen tension lead to increased blood viscosity, stasis, log jam occlusion of small blood vessels, infarction, necrosis, superinfection; damage of intima occurs most frequently in vessels with high flow rates (terminal ICA);

    • sickling occurs in areas of

      • slow flow (spleen, liver, renal medulla)

      • rapid metabolism (brain, muscle, fetal placenta)

  • chronic hemolytic anemia (increased sequestration of sickled RBCs in spleen), jaundice

  • chronic leg ulcers, priapism

  • abdominal crisis

  • rheumatism-like joint pain

  • skeletal pain (osteomyelitis, cellulitis, bone marrow infarction)

  • splenomegaly (in children + infants), later organ atrophy

    Cx: high incidence of infections (lung, bone, brain)
    Prognosis: death <40 years

  • (1) DEOSSIFICATION DUE TO MARROW HYPERPLASIA

    • porous decrease in bone density of skull (25%)

    • widening of diploe with decrease in width of outer table (22%)

    • vertical hair-on-end striations (5%)

    • osteoporosis with thinning of trabeculae

    • biconcave fish vertebrae (bone softening) in 70%

    • widening of medullary space + thinning of cortices

    • coarsening of trabecular pattern in long + flat bones

    • rib notching

    • pathologic fractures

  • (2) THROMBOSIS AND INFARCTION

    Location: in diaphysis of small tubular bones (children); in metaphysis + subchondrium of long bones (adults)

    • osteolysis (in ACUTE infarction)

    • dystrophic medullary calcification

    • periosteal reaction (bone-within-bone appearance)

    • juxtacortical sclerosis

    • Lincoln log = Reynold sign = H-vertebrae = steplike endplate depression

    • articular disintegration

    • collapse of femoral head (DDx: Perthes with involvement of metaphysis)

  • MR:

    • diffusely decreased signal of marrow on short + long TR/TE images (= hematopoietic marrow replacing fatty marrow)

    • focal areas of decreased signal intensity on short TR/TE + increased intensity on long TR/TE (= acute marrow infarction)

    • focal areas of decreased signal intensity on short TR/TE + long TR/TE images (= old infarction / fibrosis)

  • (3) SECONDARY OSTEOMYELITIS

    Organism: Salmonella in unusual frequency, also Staphylococcus

    • periostitis (DDx: indistinguishable from bone infarction)

    • dactylitis = hand-foot syndrome

  • (4) GROWTH EFFECTS (secondary to diminished blood supply)

    Location: particularly in metacarpal / phalanx

    • bone shortening = premature epiphyseal fusion

    • epiphyseal deformity with cupped metaphysis

    • cup / peg-in-hole defect of distal femur

    • diminution in vertebral height (shortening of stature + kyphoscoliosis)

  • @ Brain

    • Pathophysiology:

      • chronic anemia produces cerebral hyperemia, hypervolemia, impaired autoregulation

      • (a) cerebral blood flow cannot be increased leading to infarction in time of crisis

      • (b) increased cerebral blood flow produces epithelial hyperplasia of large intracranial vessels (terminal ICA / proximal MCA) resulting in thrombus formation

    • stroke (5 17%): ischemic infarction (70%), ischemia of deep white matter (25%), hemorrhage (20%), embolic infarction

    • Angio (in 87% abnormal):

      • arterial stenosis / occlusion of supraclinoid portion of ICA + proximal segments of ACA and MCA

      • moyamoya syndrome (35%)

      • distal branch occlusion (secondary to thrombosis / embolism)

      • aneurysm (rare)

    • CT:

      • cerebral infarction (mean age of 7.7 years)

      • subarachnoid hemorrhage (mean age of 27 years)

  • @ Chest

    • cardiomegaly + CHF

  • @ Gallbladder

    • cholelithiasis

    • P.163


  • @ Kidney

    • hematuria

    • hyposthenuria

    • nephrotic syndrome

    • renal tubular acidosis (distal)

    • hyperuricemia

    • progressive renal insufficiency

    • normal urogram (70%)

    • papillary necrosis (20%)

    • focal renal scarring (20%)

    • smooth large kidney (4%)

    • MR:

      • decreased cortical signal on T2-weighted images (renal cortical iron deposition)

  • @ Spleen

    • splenomegaly < age 10 (in patients with heterozygous sickle cell disease)

      Cx: splenic rupture

    • splenic infarction

    • hemosiderosis

  • Bone marrow scintigraphy:

    • usually symmetric marked expansion of hematopoietic marrow beyond age 20 involving entire femur, calvarium, small bones of hand + feet (normally only in axial skeleton + proximal femur and humerus)

    • bone marrow defects indicative of acute / old infarction

  • Tc-99m diphosphonate scan:

    • increased overall skeletal uptake (high bone-to-soft tissue ratio)

    • prominent activities at knees, ankles, proximal humerus (delayed epiphyseal closure / increased blood flow to bone marrow)

    • bone marrow expansion (calvarial thickening with relative decrease in activity along falx insertion)

    • decreased / normal uptake on bone scan within 24 hours in acute infarction / posthealing phase following infarction (cyst formation)

    • increased uptake on bone scan after 2 10 days persistent for several weeks in healing infarction

    • increased uptake on bone scan within 24 48 hours in osteomyelitis

    • increased blood-pool activity + normal delayed image on bone scan in cellulitis

    • renal enlargement with marked retention of tracer in renal parenchyma (medullary ischemia + failure of countercurrent system) in 50%

    • persistent splenic uptake (secondary to degeneration, atrophy, fibrosis, calcifications)

Functional Asplenia

  • = anatomically present nonfunctional spleen

  • Howell-Jolly bodies, siderocytes, anisocytosis, irreversibly sickled cells

  • normal-sized / enlarged spleen on CT

  • absence of tracer uptake on sulfur colloid scan

Autosplenectomy

  • = autoinfarction of spleen in homozygous sickle cell disease (function lost by age 5)

    Histo: extensive perivascular fibrosis with deposition of hemosiderin + calcium

  • small (as small as 5 10 mm) densely calcified spleen

Acute Splenic Sequestration Crisis

  • = sudden trapping of large amount of blood in spleen

    Cause: obstruction of small intrasplenic veins / sinusoids; unknown trigger event
    Age: (a) homozygous: infancy / childhood
    (b) heterozygous: any age

  • LUQ pain

  • sudden massive splenic enlargement

  • rapid drop in hemoglobin, hematocrit, platelets (spleen traps large volumes of blood)

  • rise in reticulocytes

  • enlarged spleen

  • multiple lesions at periphery of spleen: hypoechoic by US, of low attenuation by CT

  • hyperdense areas (due to acute hemorrhage)

  • hyperintense areas on T1WI + T2WI (due to subacute hemorrhage)

  • main splenic vessels patent by Doppler US

    Prognosis: in 50% death <2 years of age (due to hypovolemic shock)

Sickle Cell Trait

  • Hb SA carrier; mild disease with few episodes of crisis + infection; sickling provoked only under extreme stress (unpressurized aircraft, anoxia with CHD, prolonged anesthesia, marathon running)

    Incidence: in 8 10% of American Blacks

  • may have normal blood count

  • recurrent gross hematuria

  • splenic infarction

SC Disease

  • Hb SC carrier

    Incidence: 3% of American Blacks

  • retinal hemorrhages

  • hematuria due to multiple infarctions

  • aseptic necrosis of hip

Sickle-Thal Disease

  • Resembling clinically Hb SS patients

  • anemia (no normal adult hemoglobin)

  • persistent splenomegaly

Sinding-Larsen-Johansson Disease

  • = osteochondrosis of inferior pole of patella, often bilateral (NOT osteonecrosis / epiphysitis / osteochondritis)

    Cause: traction with contusion + subsequent tendinitis / traumatic avulsion of bone; repeated subluxation dislocation of patella
    Age: adolescents (often 10 14 years)
    Predisposed: cerebrospastic children

  • tenderness + soft-tissue swelling over lower pole of patella

  • peripatellar soft-tissue swelling

  • calcification / ossification of patellar tendon

  • small bone fragments at lower pole of patella (LAT view)

    • P.164


  • MR:

    • hypointense area on T1WI + hyperintense on T2WI in inferior pole of patella + surrounding soft tissues

Smallpox

  • 5% of infants

    Location: elbow bilateral; metaphysis of long bones

  • rapid bone destruction spreading along shaft

  • periosteal reaction

  • endosteal + cortical sclerosis frequent

  • premature epiphyseal fusion with severe deformity

  • ankylosis is frequent

Soft-Tissue Chondroma

  • = EXTRASKELETAL CHONDROMA = CHONDROMA OF SOFT PARTS

    Incidence: 1.5% of all benign soft-tissue tumors
    Age: 30 60 years (range 1 85 years); M:F = 1.2:1
    Histo: adult-type hyaline cartilage with areas of calcification + ossification; myxoid change; regions of increased cellularity + cytologic atypia

  • slow-growing soft-tissue mass

  • occasionally pain + tenderness

    Location: hand (54 64%) + foot (20 28%)

  • lobulated well-defined extraskeletal mass <2 cm in size

  • may contain calcifications (33 70%) with ringlike appearance / ossifications

  • scalloping of adjacent bone with sclerotic reaction

  • MR:

    • high signal intensity on T2WI

    • intermediate signal intensity on T1WI

    Rx: local excision
    Prognosis: 15 25% recurrence rate
    DDx: (1) Extraskeletal myxoid chondrosarcoma (deep-seated in large muscles of upper + lower extremities, pelvic + shoulder girdles)
    (2) Periosteal chondroma

Soft-Tissue Osteoma

  • = OSTEOMA OF SOFT PARTS (extremely rare)

    Histo: mature lamellar bone with well-defined haversian system; bone marrow, myxoid, vascular, fibrous connective tissue between bone trabeculae; collagenous capsule blending into benign hyaline cartilage
    Location: head (usually posterior part of tongue), thigh

  • ossified mass

  • NUC:

    • intense tracer accumulation, greater than adjacent bone

Solitary Bone Cyst

  • = UNICAMERAL / SIMPLE BONE CYST

    Incidence: up to 5% of primary bone lesions
    Etiology: ? trauma (synovial entrapment at capsular reflection),? vascular anomaly (blockage of interstitial drainage)
    Histo: cyst filled with clear yellowish fluid often under pressure, wall lined with fibrous tissue + hemosiderin, giant cells may be present
    Age: 3 19 years (80%); occurs during active phase of bone growth; M:F = 3:1

    • asymptomatic, unless fractured

      Location: proximal femur + proximal humerus (60 75%), fibula, at base of calcaneal neck (4%, >12 years of age), talus; rare in ribs, ilium, small bones of hand + feet (rare), NOT in spine / calvarium; solitary lesion
      Site: intramedullary centric metaphyseal, adjacent to epiphyseal cartilage (during active phase) / migrating into diaphysis with growth (during latent phase), does not cross epiphyseal plate

    • 2 3 cm oval radiolucency with long axis parallel to long axis of host bone

    • fine sclerotic boundary

    • scalloping + erosion of internal aspect of underlying cortex

    • photopenic area on bone scan (if not fractured)

    • fallen fragment sign if fractured (20%) = centrally dislodged fragment falls into a dependent position

      Prognosis: mostly spontaneous regression
      Cx: pathologic fracture (65%)
      DDx: (1) Enchondroma (calcific stipplings)
      (2) Fibrous dysplasia (more irregular lucency)
      (3) Eosinophilic granuloma
      (4) Chondroblastoma (epiphyseal)
      (5) Chondromyxoid fibroma (more eccentric + expansile)
      (6) Giant cell tumor
      (7) Aneurysmal bone cyst (eccentric)
      (8) Hemorrhagic cyst
      (9) Brown tumor

Solitary Plasmacytoma of Bone

  • = represents early stage of multiple myeloma, precedes multiple myeloma by 1 20 years

    Age: 5th 7th decade

  • negative marrow aspiration; no IgG spike in serum / urine

  • A. SOLITARY MYELOMA OF BONE

    Site: thoracic / lumbar spine (most common) > pelvis > ribs > sternum, skull, femora, humeri

    • solitary bubbly osteolytic grossly expansile lesion

    • poorly defined margins, Swiss-cheese pattern

    • frequently pathologic fracture (collapse of vertebra)

      DDx: giant cell tumor, aneurysmal bone cyst, osteoblastoma, solitary metastasis from renal cell / thyroid carcinoma

  • B. EXTRAMEDULLARY PLASMACYTOMA

    Location: majority in head + neck; 80% in nasal cavity, paranasal sinuses, upper airways of trachea, lung parenchyma

Spondyloepiphyseal Dysplasia

Spondyloepiphyseal Dysplasia Congenita

  • Autosomal dominant / sporadic (most)

  • disproportionate dwarfism with spine + hips more involved than extremities

  • waddling gait + muscular weakness

  • flat facies

  • short neck

  • deafness

  • cleft palate

    • P.165


  • @ Axial skeleton

    • ovoid vertebral bodies + severe platyspondyly (incomplete fusion of ossification centers + flattening of vertebral bodies)

    • hypoplasia of odontoid process (Cx: cervical myelopathy)

    • progressive kyphoscoliosis (short trunk) involving thoracic + lumbar spine

    • narrowing of disk spaces (resulting in short trunk)

    • broad iliac bases + deficient ossification of pubis

    • flat acetabular roof

  • @ Chest

    • bell-shaped thorax

    • pectus carinatum

  • @ Extremities

    • normal / slightly shortened limbs

    • severe coxa vara + genu valgum

    • multiple accessory epiphyses in hands + feet

    • talipes equinovarus

      Cx: (1) Retinal detachment, myopia (50%)
      (2) Secondary arthritis in weight-bearing joints

Spondyloepiphyseal Dysplasia Tarda

  • = sex-linked recessive form with milder manifestation + later clinical onset

    Age: apparent by 10 years; exclusive to males

  • hyperostotic new bone along posterior 2/3 of vertebral end plate (PATHOGNOMONIC)

  • platyspondyly with depression of anterior 1/3 of vertebral body

  • narrowing with calcification of disk spaces + spondylitic bridging

  • short trunk

  • dysplastic joints (eg, flattened femoral heads)

  • premature osteoarthritis

    DDx: Ochronosis

Sprengel Deformity

  • = failure of descent of scapula secondary to fibrous / osseous omovertebral connection

    Associated with: Klippel-Feil syndrome, renal anomalies

  • webbed neck

  • shoulder immobility

  • elevation + medial rotation of scapula

Subungual Exostosis

  • = DUPUYTREN EXOSTOSIS

    Cause: repetitive trauma (14 25%)
    Age: 2nd 3rd decade (range, 7 58 years)
    Histo: proliferating fibroblasts developing into fibrocartilage + bone
    Location: toes (86 90%, great toe in 77 80%), thumb + index finger (10 14%, dominant hand in 75%)
    Site: dorsal / dorsomedial aspect of distal phalanx

  • mass under / adjacent to nail bed rapid growth

  • may be painful with overlying skin ulceration

  • ossific mass distal to physeal scar:

  • NO continuity to cortex / medulla of host bone

  • broad / narrow base

  • indistinct / well-demarcated cartilage cap larger than base

    Rx: complete surgical excision
    Prognosis: 11 53% recurrence rate
    DDx: osteochondroma (exostosis continuous with cortex and medulla of host bone)

Superficial Fibromatoses

Infantile Digital Fibromatosis

  • = REYE TUMOR = INFANTILE DIGITAL FIBROMA = INFANTILE DIGITAL MYOFIBROBLASTOMA

  • = single / multiple nodular dermal protrusion of fibrous tissue on extensor surface of digits

    Age: 1st year of life (>80%); 30% congenital
    Histo: intracytoplasmic perinuclear inclusion bodies
    Location: fingers (60%), toes (40%)
    Site: lateral aspect of distal / middle phalanx

  • nonspecific soft-tissue mass involving a digit

  • infrequently bone involvement

    Prognosis: spontaneous regression (in 8%); 60% recurrence rate after excision

Juvenile Aponeurotic Fibroma

  • = CALCIFIED APONEUROTIC FIBROMA

  • = rare locally aggressive benign fibrous tumor

    Histo: cellular dense fibrous tissue with focal chondral elements infiltrating adjacent structures (= cartilaginous tumor)
    Age: children + adolescents (within first 2 decades of life); M:F = 2:1

  • slow-growing asymptomatic soft-tissue mass

    Location: deep palmar fascia of hand + wrist (67%); soles of feet

  • nonspecific soft-tissue mass overlying inflamed bursa (often mistaken for calcified bursitis)

  • stippled calcifications (frequent)

  • interosseous soft-tissue mass of forearm + wrist

  • erosion / scalloping of bone may occur

    Prognosis: recurrence rate of >50% after resection
    Dx: biopsy (to differentiate from synovial sarcoma)
    DDx: synovial sarcoma (commonly calcifies, bone erosion), chondroma, fibrosarcoma, osteosarcoma, myositis ossificans

Palmar Fibromatosis

  • = DUPUYTREN DISEASE

    Prevalence: 1 2%
    Age: in 24% of people >65 years; M:F = 4:1

  • subcutaneous nodules on palmar surface of distal crease of hand progressing to cords and bands

  • flexion contractures of digits (2 to fibrous attachment to flexor tendons)

    Location: 4th + 5th (most commonly) > 2nd + 3rd digit; bilateral in 42 60%

  • predominantly hypointense on T2WI + low to intermediate intensity on T1WI (in hypocellular lesions)

  • intermediate signal intensity on T2WI (proliferative hypercellular lesions)

Plantar Fibromatosis

  • = PLANTAR FASCIITIS = LEDDERHOSE DISEASE

  • = common form of superficial fibromatosis

    P.166


    Cause: trauma
    Age: 30 50 years
    Path: abnormal fibrous tissue replacing the plantar aponeurosis and infiltrating subcutaneous tissue + skin
    Histo: nonencapsulated proliferation of fibroblasts separated by variable amounts of collagen
    At risk: runners, obese patients
    Associated with (in 50%): Dupuytren contracture (10 65%), Peyronie disease

  • heel pain (one of the most common causes)

  • one / multiple firm fixed subcutaneous nodules

    Location: proximal / central portion of plantar aponeurosis; bilateral in 20 50%
    Site: medial aspect of aponeurosis

  • calcaneal spur

  • MR:

    • single or multiple nodules / poorly defined infiltrative mass iso- / hypointense compared to plantar muscles on T1WI + T2WI

    • marked contrast enhancement in 50%

    • subcutaneous edema

Synovial Osteochondromatosis

= SYNOVIAL CHONDROMATOSIS = JOINT CHONDROMA

Primary Synovial Osteochondromatosis

  • = benign self-limiting monoarticular disorder characterized by proliferation + metaplastic transformation of the synovium with formation of multiple intrasynovial cartilaginous / osteocartilaginous nodules

    Cause: hyperplastic synovium with cartilage metaplasia (foci <2 3 cm); loose body may remain free floating / conglomerate with other loose bodies into large mass / reattach to synovium with either reabsorption or continued growth
    Histo: foci of hyaline cartilage with mineralized chondroid matrix beneath synovial surface + within subsynovial connective tissue; hypercellularity + nuclear atypia may be confused with malignancy
    Composition of cartilaginous bodies:
      cartilage alone / cartilage + bone / mature bone + fatty marrow
    Age: presents in 3rd 5th decade; M:F = 2 4:1

  • slow-growing soft-tissue mass in joint

  • progressive joint pain for several years with limitation of motion / locking

  • hemorrhagic joint effusion

    Location: knee (most common with >50%, in 10% bilateral) elbow > hip > shoulder > ankle > wrist; usually monoarticular, occasionally bilateral
    Sites: joint / tendon sheath / ganglion / bursa / periarticular

  • multiple calcified / ossified loose bodies in a single joint (bony shell of remodeled lamellar bone is rare) in a rings-and-arcs morphology

  • size of nodules varies between a few mm to several cm

  • varying degrees of bone mineralization (25 30% of

  • chondromas show no radiopacity)

  • pressure erosion of adjacent bone in joints with tight capsule (eg, hip)

  • widening of joint space (from accumulation of loose bodies)

  • joint effusion uncommon

  • NO osteoporosis

  • CT:

    • multiple calcified / ossified intraarticular bodies

    • intraarticular soft-tissue mass of near-water attenuation containing multiple small calcifications

    MR:

    • lobulated intraarticular mass isointense to muscle on T1WI + hyperintense to muscle on T2WI containing multiple foci of low signal intensity

      DDx: large effusion, soft-tissue tumor

    • peripheral contrast enhancement of chondral lesions

    • central area of high-signal intensity on T1WI for intraarticular bodies with fatty marrow

    Cx: (1) Long-standing disease may lead to degenerative arthritis (from chronic mechanical irritation + destruction of articular cartilage by loose bodies)
    (2) Malignant dedifferentiation to chondrosarcoma
    Rx: removal of loose bodies (recurrence is common)
    DDx: (1) Synovial sarcoma, chondrosarcoma
    (2) Osteochondral fracture (history of trauma), osteochondritis dissecans, osteonecrosis
    (3) Secondary osteochondromatosis
    (4) Pigmented villonodular synovitis, synovial hemangioma, lipoma arborescens

Secondary Synovial Osteochondromatosis

  • = joint surface disintegration

    Cause: trauma, osteonecrosis, rheumatoid arthritis, neuropathic arthropathy, tuberculous arthritis, degenerative joint disease

  • intraarticular bodies tend to be larger, less numerous, more varied in size compared to primary synovial osteochondromatosis

  • prominent osteoarthritis

Synovioma

  • = SYNOVIAL SARCOMA

  • = slow-growing expansile malignant tumor originating in the synovial lining / bursa / tendon sheath; uncommonly intraarticular

    Incidence: 10% of soft-tissue sarcomas
    Histo: fibrosarcomatous (spindle cell) with areas of hyalinization + synovial (epithelial cell) component
    Age: 3rd 5th decade; M:F = 2:3

  • painful soft-tissue mass

    Location: lower extremity (2/3): knee (most common), hip, ankle; upper extremity (1/3): elbow, wrist, hands, feet; usually solitary

  • large spheroid well-defined soft-tissue mass

  • lesion about 1 cm removed from joint cartilage

  • amorphous punctate calcifications / ossification (1/3), often at periphery of tumor

    • Calcification in other soft-tissue connective tissue sarcomas is uncommon!

  • involvement of adjacent bone (11 20%):

    • periosteal reaction

    • bone remodeling (pressure from tumor)

      • P.167


    • invasion of cortex with wide zone of transition

  • juxtaarticular osteoporosis

  • MR:

    • poorly defined + infiltrative

    • low signal intensity on T1WI; high signal intensity on T1WI from hemorhage

    • inhomogeneous tumor: hyperintense (cystic) + isointense (solid) + hypointense (fibrous) elements on T2WI

    • multilocular appearance with internal septation

    • fluid-fluid levels (previous hemorrhage)

    Rx: local excision / amputation + radiation / chemotherapy

Syphilis of Bone

Congenital Syphilis

  • Transplacental transmission cannot occur <16 weeks gestational age

  • positive rapid plasma reagin (measures quantity of antibodies to assess new infection / efficacy of Rx)

  • positive microhemagglutination test for Treponema pallidum (remains reactive for life)

  • pneumonia alba

  • hepatomegaly

    Location: symmetrical bilateral osteomyelitis involving multiple bones (HALLMARK)

  • A. Early phase

    • Skeletal radiography abnormal in 19% of infected newborns without overt disease!

    • 1. Metaphysitis

      • lucent metaphyseal band adjacent to thin / widened zone of provisional calcification (disturbance in enchondral bone growth)

      • frayed edge of metaphyseal-physeal junction (osteochondritis) = erosions + lytic defects

    • 2. Diaphyseal periostitis = luetic diaphysitis

      • solid / lamellated periosteal new-bone growth = bone-within-bone appearance

    • 3. Spontaneous epiphyseal fractures causing Parrot pseudopalsy (DDx: battered child syndrome)

    • 4. Bone destruction

      • marginal destruction of spongiosa + cortex along side of shaft with widening of medullary canal (in short tubular bones)

      • patchy rarefaction in diaphysis

    • 5. Wimberger sign

      • symmetrical focal bone destruction of medial portion of proximal tibial metaphysis (ALMOST PATHOGNOMONIC)

  • B. Late phase

    • Hutchinson triad = dental abnormality, interstitial keratitis, 8th nerve deafness

    • frontal bossing of Parrot = diffuse thickening of outer table

    • saddle nose + high palate (syphilitic chondritis + rhinitis)

    • short maxilla (maxillary osteitis)

    • thickening at sternal end of clavicle

    • saber-shin deformity = anteriorly convex bowing in upper 2/3 of tibia with bone thickening

Acquired Syphilis

  • = TERTIARY SYPHILIS resembles chronic osteomyelitis

  • dense bone sclerosis of long bones

  • irregular periosteal proliferation + endosteal thickening with narrow medulla

  • extensive calvarial bone proliferation with mottled pattern (anterior half + lateral skull) in outer table (DDx: fibrous dysplasia, Paget disease)

  • ill-defined lytic destruction in skull, spine, long bones (gumma formation)

  • enlargement of clavicle (cortical + endosteal new bone)

  • Charcot arthropathy of lower extremities + spine

Tarsal Coalition

  • = abnormal fibrous / cartilaginous / osseous fusion of two or more tarsal ossification bones

  • Clinically most important congenital problem of calcaneus

    Prevalence: 1 2% of population
    Cause: abnormal segmentation of primitive mesenchyme with lack of joint formation
    Age: fibrous coalition at birth, ossification during 2nd decade of life with onset of symptoms; M:F = 1:1

  • asymptomatic; often first noted after antecedent trauma / weight gain / increase in athletic activity

  • peroneal spastic / rigid pes planus (=flatfoot) in adjustment for calcaneus valgus (= heel valgus)

  • hindfoot / tarsal pain or stiffness

  • both feet affected in 20 50%

  • osseous bars between bones of hindfoot / bones in close proximity with irregular surfaces

  • MR (of joint space):

    • bone marrow contiguity (osseous coalition)

    • fluid- / cartilage-intensity (cartilaginous coalition)

    • intermediate- to low-signal intensity (fibrous coalition)

    • reactive periarticular bone changes

    • bone marrow edema along fused joint (STIR images)

  • Types:

    • Calcaneonavicular coalition (45%)

      Age: 8 12 years (due to earlier ossification)

      • rigid flat foot pain in 2nd decade of life

      • Radiographs:

        • narrowed calcaneonavicular joint with indistinct articular margins (bones that usually do not articulate)

        • widening / flattening of anteromedial calcaneus

        • anteater's nose = elongation of anterior dorsal calcaneus on lateral radiograph

        • hypoplastic talar head

      • CT (axial scan):

        • broadening of medial aspect of anterodorsal calcaneus in apposition to navicular

        • narrowing of space between the 2 bones + minimal marginal reactive sclerosis

        Dx: mostly diagnosed on 45 internal oblique films

    • Talocalcaneal coalition (45%)

      Age: 12 16 years

      • painful peroneal spastic flat foot, relieved by rest

        Site: middle facet at level of sustentaculum tali (most frequently)

        • P.168


      • Secondary radiographic signs (due to alteration in hindfoot biomechanics):

        • prominent talar beak (66%) arising from dorsal aspect of head / neck of talus (due to impaired subtalar joint motion)

        • rounding of the lateral talar process

        • narrowing of posterior subtalar joint

        • lack of depiction of middle facets

        • asymmetric anterior talocalcaneal joint

        • ball-in-socket ankle mortise in severe cases

        • C sign = C-shaped outline of the medial talar dome + posteroinferior sustentaculum on lateral radiograph (from bone bridge between talar dome + sustentaculum)

      • CT (coronal scan):

        • bony bar bridging the middle facet of subtalar joint

        • narrowed middle facet with reactive cystic + hypertrophic changes

        • downward or horizontal slope of sustentaculum, instead of upward

        Dx: requires cross-sectional imaging for diagnosis

    • Talonavicular coalition

    • Calcaneocuboid coalition

    • Cubonavicular coalition

    Rx: orthotics, casting, NSAID, steroid injections, physical therapy, resection, arthrodesis
    DDx: acquired intertarsal ankylosis (infection, trauma, arthritis, surgery)

Tarsal tunnel syndrome

  • = entrapment / compression neuropathy (analogous to carpal tunnel syndrome) of

    • posterior tibial nerve (most common)

    • its terminal branches (= medial and lateral plantar nn., medial calcaneal n.)

    Tarsal tunnel = fibro-osseous passageway from level of medial malleolus to navicular bone distally
    Medial floor: tibia, talus, sustentaculum tali, medial wall of calcaneus
    Lateral roof: deep fascia of leg, flexor retinaculum = lacinate lig., abductor hallucis
    Contents: medial ankle tendons (tibialis posterior, flexor hallucis longus, flexor digitorum longus) + posterior tibial nerve and artery and veins

  • Cause:

    • intrinsic (mass effect): ganglion cyst, neural sheath tumor, lipoma, tenosynovitis of flexor hallucis longus, marked varicosities, accessory muscle, fracture, fibrosis of chronic ankle sprain, rheumatoid arthritis, diabetes

    • extrinsic (tension): tarsal colation, excessive pronation, valgus / varus heel, repetitive stress (jogger's foot)

  • burning pain, tingling, numbness, nocturnal paresthesia along plantar surface of heel, foot and toes

  • radiation of paresthesia to medial aspect of calf (Valleix phenomenon)

  • positive Tinel sign = percussion of posterior tibial n. posteroinferiorly from medial malleolus causes paresthesia

  • mass in tarsal tunnel (ganglion, neurilemoma, lipoma, thickened flexor retinaculum, muscle)

  • muscle edema from denervation in abductor hallucis (supplied by medial plantar nerve) / abductor digiti minimi (supplied by lateral plantar nerve)

  • fracture of sustentaculum tali / medial tubercle of posterior talar process

  • serpiginous varicosities

    Rx: orthotics, release

Thalassemia Syndromes

  • = inherited disorders of hemoglobin synthesis typically seen in individuals of Mediterranean descent

  • Physiologic hemoglobins:

    • in adulthood:

      • Hb A (98% = 2 - and 2 -chains);

      • Hb A2(2% = 2 - and 2 -chains)

    • in fetal life:

      • Hb F (= 2 - and 2 -chains)

      • rapidly decreasing up to 3 months of newborn period

  • A. ALPHA-THALASSEMIA

    • = decreased synthesis of a-chains leading to excess of -chains + -chains (Hb H = 4 -chains; Hb Bart = 4 -chains)

    • disease begins in intrauterine life as no fetal hemoglobin is produced

    • homozygosity is lethal (lack of oxygen transport)

  • B. BETA-THALASSEMIA

    • = decreased synthesis of -chains leading to excess of -chains + -chains (= fetal hemoglobin)

    • disease manifest in early infancy

    • (a) homozygous defect = thalassemia major = Cooley anemia

    • (b) heterozygous defect = thalassemia minor

Thalassemia Major

  • = COOLEY ANEMIA = MEDITERRANEAN ANEMIA

  • = HEREDITARY LEPTOCYTOSIS = -THALASSEMIA

  • = most severe form with trait inherited from both parents (= homozygous form)

    Incidence: 1% for American Blacks; 7.4% for Greek population; 10% for certain Italian populations
    Age: develops after newborn period within first 2 years of life

  • retarded growth

  • elevated serum bilirubin

  • hyperpigmentation of skin

  • hyperuricemia

  • secondary sexual characteristics retarded, normal menstruation rare (primary gonadotropin insufficiency from iron overload in pituitary gland)

  • hypochromic microcytic anemia (Hb 2 3 g/dL), nucleated RBC, target cells, reticulocytosis, decrease in RBC survival, leukocytosis

  • susceptible to infection (leukopenia secondary to splenomegaly)

  • bleeding diathesis (secondary to thrombocytopenia)

  • @ Skull:

    • mongoloid facies

    • marrow expansion of diploe:

      • widening of diploic space with coarsened trabeculations and displacement (from marrow hyperplasia = extramedullary hematopoiesis)

        • P.169


      • thinning of outer table

      • frontal bossing

      • severe hair-on-end appearance (frontal bone, NOT inferior to internal occipital protuberance)

    • marrow expansion in paranasal sinuses:

      • impaired pneumatization of maxillary antra + mastoid sinuses

      • narrowing of nasal cavity

      • rodent facies = ventral displacement of incisors (marrow overgrowth in maxillary bone) with dental malocclusion

    • lateral displacement of orbits

  • @ Peripheral skeleton:

    • earliest changes in small bones of hands + feet (>6 months of age)

    • diffuse osteopenia:

    • atrophy + coarsening of trabeculae (from marrow hyperplasia)

    • prominence of nutrient foramina

    • widened medullary spaces with thinning of cortices

    • Erlenmeyer flask deformity = bulging of normally concave outline of metaphyses

    • premature fusion of epiphyses (10%), usually at proximal humerus + distal femur

    • arthropathy (secondary to hemochromatosis + CPPD + acute gouty arthritis)

    • regression of peripheral skeletal changes (as red marrow becomes yellow)

  • @ Chest:

    • cardiac enlargement + congestive heart failure (secondary to anemia)

    • paravertebral masses (= extramedullary hematopoiesis)

  • @ Ribs

    • costal osteomas = bulbous widening of posterior aspect of ribs with thinned cortices

    • undertubulated broad ribs

    • heterogeneous rib ossification:

      • localized lucencies

      • cortical erosion

      • rib-within-rib appearance

  • @ Abdomen:

    • hepatosplenomegaly

    • gallstones

    Cx: (1) Pathologic fractures
    (2) Iron overload + hemosiderosis from frequent blood transfusion therapy (absent puberty, diabetes mellitus, adrenal insufficiency, myocardial insufficiency)
    Prognosis: usually death within 1st decade
    Rx: systematic transfusion has lessened the severity of skeletal abnormalities
    DDx: chronic anemia, storage diseases, fibrous dysplasia

Thalassemia Intermedia

  • = subgroup of homozygous form

  • milder clinical presentation

  • not requiring hypertransfusion to maintain an adequate hematocrit

Prognosis: longer life expectancy

Thalassemia Minor

  • = beta-thalassemia trait inherited from one parent (= heterozygous)

  • usually asymptomatic except for periods of stress (pregnancy, infection)

  • microcytic hypochromic anemia (Hb 9 11 g/dL)

  • occasionally jaundice + splenomegaly

Thanatophoric Dysplasia

  • = sporadic lethal skeletal dysplasia characterized by severe rhizomelia (micromelic dwarfism) transmitted by a dominant gene mutation

    Incidence: 6.9:100,000 births; 1:6,400 16,700 births;
        Most common lethal bone dysplasia after osteogenesis imperfecta type II

  • severe respiratory distress (early in life)

  • hypotonic infants

  • protuberant abdomen

  • extended arms + abducted externally rotated thighs

  • @ Head

    • large head with short base of skull + prominent frontal bone

    • occasionally trilobed cloverleaf skull = Kleeblattsch del

  • @ Chest radiograph (PATHOGNOMONIC)

    • narrow chest

    • short horizontal ribs:

      • not extending beyond anterior axillary line

      • cupped anterior ends

    • short curved telephone handle humeri

    • H- / U-shaped vertebra plana

    • small scapula + normal clavicles

  • @ Spine

    • normal length of trunk

    • reduction of interpediculate space of last few lumbar vertebrae

    • extreme generalized platyspondyly = severe H- / U-shaped vertebra plana

    • excessive intervertebral space height

  • @ Pelvis (hypoplastic iliac bones)

    • iliac wings small + square (vertical shortening but wide horizontally)

    • flat acetabulum

    • narrow sacrosciatic notch

    • short pubic bones

  • @ Extremities

    • severe micromelia + bowing of extremities

    • metaphyseal flaring = telephone handle appearance of long bones

    • thornlike projections in metaphyseal area

    • polydactyly

  • OB-US (findings may be seen very early in pregnancy):

    • polyhydramnios (71%)

    • short-limbed dwarfism with extremely short + bowed telephone receiver -like femurs

    • extremely small hypoplastic thorax with short ribs + narrowed in anteroposterior dimension

    • protuberant abdomen

    • macrocrania with frontal bossing hydrocephalus (increased HC:AC ratio)

    • cloverleaf skull (in 14%) (DDx: encephalocele)

      • P.170


    • diffuse platyspondyly

    • redundant soft tissues

    Prognosis: often stillborn; uniformly fatal within a few hours / days after birth (respiratory failure)
    DDx: (1) Ellis-van Creveld syndrome (extra digit, acromesomelic short limbs)
    (2) Asphyxiating thoracic dysplasia (less marked bone shortening, vertebrae spared)
    (3) Short-rib polydactyly syndrome
    (4) Homozygous achondroplasia
    (5) Achondrogenesis

Thrombocytopenia-Absent Radius Syndrome

  • = TAR SYNDROME

  • = rare autosomal recessive disorder

    Age: presentation at birth
    May be associated with: CHD (33%): ASD, tetralogy

  • platelet count <100,000/mm3 (decreased production by bone marrow)

  • usually bilateral radial aplasia / hypoplasia

  • uni- / bilaterally hypoplastic / absent ulna / humerus

  • defects of hands, feet, legs

    Prognosis: death in 50% in early infancy (hemorrhage)

Thyroid Acropachy

Onset: after >18 months following surgical / radioactive ablation of thyroid gland for hyperthyroidism (does not occur with antithyroid medication)
Incidence: 0.5 1% of patients with thyrotoxicosis

  • clubbing, soft-tissue swelling, NO pain

  • eu- / hypo- / hyperthyroid state

    Location: metacarpals + phalanges of hand; less commonly feet, lower legs, forearms

  • thick spiculated lacy feathery periosteal reaction in an asymmetric distribution; mostly on radial aspect of bone

DDx: (1) Pulmonary osteoarthropathy (painful)
(2) Pachydermoperiostosis
(3) Fluorosis (ligamentous calcifications)

Transient Regional Osteoporosis

= TRANSIENT BONE MARROW EDEMA

Cause: unknown;? overactivity of sympathetic nervous system + local hyperemia similar to reflex sympathetic dystrophy syndrome, trauma, synovitis, transient ischemia

Regional Migratory Osteoporosis

  • = rapid onset of self-limiting episodes of severe localized osteoporosis and pain but repetitive occurrence of same symptoms in other regions of the same or opposite lower extremity

  • rapid onset of local pain

  • diffuse erythema, swelling, increased heat

  • significant disability due to severe pain on weight bearing

    Age: middle-aged males
    Location: usually lower extremity (ie, ankle, knee, hip, foot)

  • rapid localized osteoporosis within 4 8 weeks after onset migrating from one joint to another; may affect trabecular / cortical bone

  • linear / wavy periosteal reaction

  • preservation of subchondral cortical bone

  • no joint space narrowing, bone erosion

  • MR:

    • affected area has low signal intensity on T1WI, high signal intensity on T2WI (= bone marrow edema)

  • NUC:

    • increased activity

    Prognosis: persists for 6 9 months in one area; cycle of symptoms may last for several years
    Rx: variable response to analgesics / corticosteroids

Partial Transient Osteoporosis

  • = variant of regional migratory osteoporosis with more focal pattern of osteoporosis, which may eventually become more generalized

  • (a) Zonal form = portion of bone involved, ie, one femoral condyle / one quadrant of femoral head

  • (b) Radial form = only one / two rays of hand / foot involved

Transient Osteoporosis of Hip

  • = self-limiting disease of unknown etiology

    Age: typically in middle-aged males / in 3rd trimester of pregnancy in females involving left hip; M > F

  • spontaneous onset of hip and groin pain, usually progressive over several weeks

  • painful swelling of joint followed by progressive

  • demineralization

  • rapid development of disability, limp, decreased range of motion

    Site: hip most commonly affected; generally only one joint at a time

  • progressive marked osteoporosis of femoral head, neck, acetabulum (3 8 weeks after onset of illness)

  • virtually PATHOGNOMONIC striking loss of subchondral cortex of femoral head + neck region

  • NO joint space narrowing / subchondral bone collapse

  • NUC:

    • markedly increased uptake on bone scan without cold spots / inhomogeneities (positive before radiograph)

  • MR:

    • diffuse bone marrow edema involving femoral head + neck + sometimes intertrochanteric region

    • small joint effusion

    Cx: pathologic fracture common
    Prognosis: spontaneous recovery within 2 6 months; recurrence in another joint within 2 years possible
    DDx: (1) AVN (cystic + sclerotic changes, early subchondral undermining)
    (2) Septic / tuberculous arthritis (joint aspiration!)
    (3) Monoarticular rheumatoid arthritis
    (4) Metastasis
    (5) Reflex sympathetic dystrophy
    (6) Disuse atrophy
    (7) Synovial chondromatosis
    (8) Villonodular synovitis

Transient Synovitis of Hip

  • = OBSERVATION HIP = TRANSITORY SYNOVITIS = TOXIC SYNOVITIS = COXITIS FUGAX

    • P.171


  • = nonspecific inflammatory reaction

  • Most common nontraumatic cause of acute limp in a child

    Etiology: unknown; no organism on joint aspiration
    Age: 5 10 (average 6) years; M:F = 2:1

  • history of recent viral illness (65%)

  • developing limp over 1 2 days

  • pain in hip, thigh, knee

  • mild fever (25%), mildly elevated ESR (50%)

  • radiographs usually normal

  • joint effusion:

    • displacement of femur from acetabulum

    • displacement of psoas line

    • lateral displacement of gluteal line (least sensitive + least reliable)

  • regional osteoporosis (? hyperemia, disuse)

  • NUC:

    • normal / slight increase in activity (excluding osteomyelitis + avascular necrosis)

    Prognosis: complete recovery within a few weeks
    Dx: per exclusion
    Rx: non weight-bearing treatment
    DDx: trauma, Legg-Perthes disease, acute rheumatoid arthritis, acute rheumatic fever, septic arthritis, tuberculosis, malignancy

Treacher-Collins Syndrome

  • = MANDIBULOFACIAL DYSOSTOSIS

  • = autosomal dominant disease (with new mutations in 60%) characterized by bilateral malformations of eyes, malar bones, mandible, and ears resulting in birdlike face

    Incidence: 1:50,000 births
    Cause: defect in growth of 1st + 3rd branchial arches before the 7th to 8th week of gestation

  • NO limb anomalies (important DDx!)

  • extension of scalp hair growth onto cheek

  • microstomia

  • craniosynostosis

  • narrowing of retropharyngeal space (apnea, speech difficulties)

  • @ Eyes

    • antimongoloid eye slant (drooping lateral lower eyelids due to hypoplasia of lateral canthal tendon of orbicular muscle)

    • sparse / absent eye lashes / coloboma in lower lids

    • egg-shaped orbits = drooping of outer inferior orbital rim

    • hypoplasia of lateral wall of orbits + shallow / incomplete orbital floor

  • @ Nose

    • broad / protruded nose

    • choanal shortening

  • @ Malar bone

    • sunken cheek due to marked hypoplasia / agenesis of zygomatic arches (= malar hypoplasia)

  • @ Maxilla

    • hypoplasia of maxilla + maxillary sinus

    • narrow / overprojected maxilla

    • high-arched / narrow palate

  • @ Mandible

    • retruded chin, retrognathism

    • dental malocclusion

    • pronounced micrognathia = mandibular hypoplasia with broad concave curve on lower border of body

  • @ Ear

    • dysplastic low-set auricles

    • preauricular skin tags / fistulas

    • conductive hearing loss (common)

    • microtia with small middle ear cavity

    • deformed / fused / absent auditory ossicles

    • atresia / stenosis of external auditory canal

  • OB-US:

    • polyhydramnios (from swallowing difficulty)

    Prognosis: early respiratory problems (tongue relatively too large for hypoplastic mandible)
    Rx: surgical correction
    DDx: (1) Goldenhar-Gorlin syndrome (unilateral microtia + midface anomalies, hemivertebrae, block vertebrae, vertebral hypoplasia, microphthalmia, coloboma of upper lid)
    (2) Acrofacial dysplasia (limb malformations)
    (3) Crouzon disease (maxillary hypoplasia with protrusion of mandible, hypertelorism, exophthalmos, craniosynostosis)

Trisomy D Syndrome

  • = Trisomy 13 15 group syndrome

    Etiology: additional chromosome in D group; high maternal age

  • severe mental retardation

  • hypertonic infant

  • cleft lip + palate

    Associated with: capillary hemangioma of face + upper trunk

  • hypotelorism

  • coloboma, cataract, microphthalmia

  • malformed ear with hypoplastic external auditory canal

  • hyperconvex nails

  • postaxial polydactyly

  • @ Skull

    • deficient ossification of skull

    • cleft / absent midline structures of facial bones

    • poorly formed orbits

    • slanting of frontal bones

    • microcephaly

    • arrhinencephaly

    • holoprosencephaly

  • @ Chest

    • thin malformed ribs

    • diaphragmatic hernia (frequent)

    • congenital heart disease

    Prognosis: death within 6 months of age

Trisomy E Syndrome

  • = Trisomy 16 18 group syndrome

    Etiology: additional chromosome at 18 or E group location
    Sex: usually female

  • Marked phenotypic variability!

  • hypertonic spastic infants

  • mental + psychomotor retardation

  • typical facies: micrognathia, high narrow palate with small buccal cavity, low-set deformed ears

    • P.172


  • flexed ulnar-deviated fingers + short adducted thumb

  • 2nd finger overlapping of 3rd (CHARACTERISTIC)

    Associated with: congenital heart disease in 100% (PDA, VSD); hernias; renal anomalies; eventration of diaphragm

  • stippled epiphyses

  • @ Skull

    • thin calvarium

    • persistent metopic suture

    • dolichocephaly with prominent occiput

    • micrognathia due to hypoplastic mandible (most constant feature) + maxilla

  • @ Chest

    • increase in AP diameter of thorax

    • shield deformity due to hypoplastic short sternum

    • hypoplastic clavicles (DDx: cleidocranial dysostosis)

    • 11 rib pairs with slender hypoplastic + tapered ribs

    • diaphragmatic eventration (common)

  • @ Pelvis

    • small pelvis with forward rotation of iliac wings

    • increased obliquity of acetabulum

    • acute iliac angle (DIAGNOSTIC)

  • @ Hand & foot

    • adducted thumb = short 1st metacarpal + phalanges (DIAGNOSTIC)

    • overlap of 2nd on 3rd finger (DIAGNOSTIC)

    • flexed ulnar-deviated fingers

    • short 1st toe

    • varus deformities of forefoot + dorsiflexion of toes

    • rocker bottom foot / extreme pes planus (frequent)

  • OB-US:

    • hydrocephalus

    • cystic hygroma

    • diaphragmatic hernia

    • clubfoot

    • overlapping index finger

    • choroid plexus cyst (30%)

    Prognosis: child rarely survives beyond 6 months of age
    DDx: osteogenesis imperfecta, trisomy 13 syndrome, Cockayne syndrome, Werdnig-Hoffmann disease

Tuberculosis of Bone

Incidence: 1 3 5% of tuberculous patients, 30% in patients with extrapulmonary tuberculosis
Age: any, rare in 1st year of life, M:F = 1:1

  • negative skin test excludes diagnosis

  • history of active pulmonary disease (in 50%)

    Location: vertebral column, hip, knee, wrist, elbow
    Associated with: concurrent active intrathoracic tuberculosis in <50%

  • Pathogenesis:

    • Hematogenous spread from

      • primary infection of lung (particularly in children)

      • quiescent primary pulmonary site / extraosseous focus

    • Reactivation: especially in hip

Tuberculous Arthritis

  • = joint involvement usually secondary to adjacent osteomyelitis / hematogenous dissemination

    Incidence: 84% of skeletal tuberculosis
    Pathophysiology: synovitis with pannus formation leads to chondronecrosis
    Age: middle-aged / elderly

  • chronic pain, weakness, muscle wasting

  • soft-tissue swelling, draining sinus

  • joint fluid: high WBC count, low glucose level, poor mucin clot formation (similar to rheumatoid arthritis)

    Location: hip, knee (large weight-bearing joints) >> elbow, wrist, sacroiliac joint, glenohumeral, articulation of hand + foot
    Monoarticular involvement is typical!

  • Phemister triad:

    • Gradual narrowing of joint space due to slow cartilage destruction (DDx: cartilage destruction in pyogenic arthritis is much quicker)

    • Peripherally located (= marginal) bone erosions

    • Juxtaarticular osteoporosis

      (DDx: fungal disease, rheumatoid arthritis)

  • Early radiographs:

    • joint effusion (hip in 0%, knee in 60%, ankle in 80%)

    • extensive periarticular osteopenia (deossification) adjacent to primarily weight-bearing joints

    • soft tissues normal

  • Late radiographs:

    • small cystlike erosions along joint margins in non weight-bearing line opposing one another (DDx: pyogenic arthritis erodes articular cartilage)

    • no joint space narrowing for months (CLASSIC!)

    • articular cortical bone destruction earlier in joints with little unopposed surfaces (hip, shoulder)

    • kissing sequestra = wedge-shaped areas of necrosis on both sides of the joint due to infection of subchondral bone

    • increased density with extensive soft-tissue calcifications in healing phase

    Cx: fibrous ankylosis, leg shortening
    Dx: synovial biopsy (in 90% positive), culture of synovial fluid (in 80% positive)
    DDx: pyogenic arthritis (central erosion of articular cartilage, early joint space narrowing, bony ankylosis)

Tuberculous Osteomyelitis

Incidence: 16% of skeletal tuberculosis
Age: children <5 years (0.5 14%), rare in adults

  • painless swelling of hand / foot

    Location: femur, tibia, small bones of hand + foot (most common); any bone may be involved

  • Site:

    • metaphysis (TYPICALLY) with transphyseal spread (in child) (DDx: pyogenic infections usually do not extend across physis)

    • epiphysis with spread to joint / spread from adjacent affected joint

    • diaphysis (<1%)

  • initially round / oval poorly defined lytic lesion with minimal / no surrounding sclerosis

  • varying amounts of eburnation + periostitis

  • advanced epiphyseal maturity / overgrowth (due to hyperemia) limb shortening from premature physeal fusion

    • P.173


  • cystic tuberculosis = well-marginated round / oval radiolucent lesions with variable amount of sclerosis

    • in children (frequent): in peripheral skeleton, symmetric distribution, no sclerosis

    • in adults (rare): in skull / shoulder / pelvis / spine, with sclerosis

      (DDx: eosinophilic granuloma, sarcoidosis, cystic angiomatosis, plasma cell myeloma, chordoma, fungal infections, metastases)

  • tuberculous dactylitis = digit with exuberant lamellated / solid periosteal new-bone formation and fusiform soft-tissue swelling (children >> adults):

    • spina ventosa ( wind-filled sail ) = ballooning dactylitis forming an enlarging cystlike cavity with erosion of endosteal cortex (end-stage disease)

    DDx: (1) pyogenic osteomyelitis (no transphyseal spread)
    (2) syphilitic dactylitis (bilateral symmetric involvement, less soft-tissue swelling and sequestration)
    (3) Sarcoidosis, hemoglobinopathies, hyperparathyroidism, leukemia

Tuberculous Spondylitis

  • = POTT DISEASE

  • [Percival Pott (1714 1788), surgeon in London, England associated cancer of the scrotum with coal tar in chimney sweeps]

  • = destruction of vertebral body + intervertebral disk by tuberculous mycobacterium

    Incidence: 5% of patients with tuberculosis; 25 50 60% of all skeletal tuberculosis
    Age: children / adults of 50 years; M > F

  • insidious onset of back pain, stiffness

  • local tenderness

  • NO pulmonary lesions in 50%

    Location: upper lumbar + lower thoracic spine (L1 most common); TYPICALLY more than one (up to 5 10) vertebrae affected
    Site: vertebral body (82%) with predilection for anterior part adjacent to superior / inferior sub-chondral bone plate >> posterior elements (18%)

  • Spread:

    • contiguous into disk by penetrating subchondral endplate + cartilaginous endplate

    • subligamentous spread beneath anterior / posterior longitudinal ligaments to adjacent vertebral bodies

    • hematogenous spread via paravertebral venous plexus of Batson: separate foci in 1 4%

  • collapse of intervertebral disk space

    N.B.: vertebral disk space maintained longer than in pyogenic arthritis (disk itself preserved but fragmented)

  • demineralization (= resorption of dense margin) of vertebral endplates:

    • gouge defect = mild contour irregularity of anterior and lateral aspect of vertebral body (= erosion from subligamentous extension of tuberculous abscess)

    • reactive sclerosis / periosteal reaction TYPICALLY absent

  • collapse of vertebral body:

    • vertebra plana in children

    • angular kyphotic deformity (= gibbus) due to preferential anterior involvement in adults

  • vertebra within a vertebra (= growth recovery lines)

  • ivory vertebra (= reossification as healing response to osteonecrosis)

  • paraspinal infection:

    • large cold fusiform abscess in paravertebral gutters / psoas, commonly bilateral anterolateral scalloping of vertebral bodies

    • amorphous / teardrop-shaped calcification in paraspinal area between L1 + L5 (DDx: nontuberculous abscess rarely calcifies)

    • abscess may extend into groin / thigh / internal viscus

    Cx: angular kyphosis (= gibbus deformity), scoliosis, ankylosis, osteonecrosis, paralysis (spinal cord compression from abscess, granulation tissue, bone fragments, arachnoiditis)
    Prognosis: 26 30% mortality rate
    DDx: (1) Pyogenic spondylitis (rapid destruction, multiple abscess cavities, no thickening / calcification of abscess rim, little new-bone formation, posterior elements not involved)
    (2) Brucellosis (gas within disk, minimal paraspinal mass, no kyphosis, predilection for lower lumbar spine)
    (3) Sarcoidosis
    (4) Neoplasia (multiple noncontiguous lesions, no disk destruction, little soft-tissue involvement)

Tuberculous Spondylitis without Diskitis

  • increasingly more common type of TB

    Predilection: foreign-born (sub-Saharan Africa)
    Age: 40 years (10 years younger)

  • absence of disk destruction

  • initial multifocal vertebral involvement in 42%

  • extraspinal skeletal involvement (frequent)

Tumoral Calcinosis

  • = LIPOCALCINOGRANULOMATOSIS

  • = rare disease with progressive large nodular juxtaarticular calcified soft-tissue masses in patients with normal serum calcium + phosphorus and no evidence of renal, metabolic, or collagen-vascular disease

    Etiology: autosomal dominant (1/3) with variable clinical expressivity; unknown biochemical defect of phosphorus metabolism responsible for abnormal phosphate reabsorption + 1,25-dihydroxy-vitamin D formation
    Path: multilocular cystic lesions with creamy white fluid (hydroxyapatite) + many giant cells (granulomatous foreign body reaction) surrounded by fibrous capsule
    Age: onset mostly within 1st / 2nd decade (range of 1 79 years); M:F = 1:1; predominantly in Blacks

  • progressive painful / painless soft-tissue mass with overlying skin ulceration + sinus tract draining chalky milklike fluid

  • swelling

  • limitation of motion

  • hyperphosphatemia + hypervitaminosis D

  • normal serum calcium, alkaline phosphatase, renal function, parathyroid hormone

    • P.174


  • @ Soft tissue

    Location: paraarticular in hips > elbows > shoulders > feet, ribs, ischial spines; single / multiple joints; ALMOST NEVER knees; usually along extensor surface of joints (? initially a calcific bursitis)

    • dense loculated multiglobular homogeneously calcified soft-tissue mass of 1 20 cm in size

    • cystic appearance with radiolucent septa (= connective tissue)

    • sedimentation sign = fluid-fluid levels with milk-of-calcium consistency

    • underlying bones NORMAL

    • increased tracer uptake of soft-tissue masses on bone scan

    • MR:

      • inhomogeneous high signal intensity on T2WI (in spite of large amount of calcium)

      • inhomogeneous lesion with low signal intensity on T1WI

  • @ Bone

    • diaphyseal periosteal reaction (diaphysitis)

    • patchy areas of calcification in medullary cavity (calcific myelitis)

    • increased uptake on bone scintigraphy

  • @ Teeth

    • bulbous root enlargement

    • pulp stones = intrapulp calcifications

  • @ Pseudoxanthoma elasticum-like features

    • calcinosis cutis = skin calcifications

    • vascular calcifications

    • angioid streaks of retina

    Prognosis: tendency for recurrence after incomplete excision
    Rx: phosphate depletion
    DDx: Chronic renal failure on hemodialysis, CPPD, paraosteoarthropathy, hyperparathyroidism

Turner Syndrome

  • = due to nondisjunction of sex chromosomes as

    • complete monosomy (45, XO)

    • partial monosomy (structurally altered second X chromosome)

    • mosaicism (XO + another sex karyotype)

    Incidence: 1:3,000 5,000 livebirths
    Associated with: coarctation, aortic stenosis, horseshoe kidney (most common)

  • sexual infantilism (spontaneous puberty in 5 15%):

    • primary amenorrhea

    • absent secondary sex characteristics

  • short stature; absence of prepubertal growth spurt

  • webbed neck; low irregular nuchal hair line

  • shield-shaped chest + widely spaced nipples

  • mental deficiency (occasionally)

  • high palate; thyromegaly

  • multiple pigmented nevi; keloid formation

  • idiopathic hypertension; elevated urinary gonadotropins

  • @ General

    • normal skeletal maturation with growth arrest at skeletal age of 15 years

    • delayed fusion of epiphyses > age 20 years

    • osteoporosis during / after 2nd decade (gonadal hormone deficiency)

    • coarctation of aorta (10%); aortic stenosis

    • renal ectopia / horseshoe kidney

    • lymphedema

  • @ Skull

    • basilar impression; basal angle >140

    • parietal thinning

    • small bridged sella

    • hypertelorism

  • @ Axial skeleton

    • hypoplasia of odontoid process + C1

    • osteochondrosis of vertebral plates

    • squared lumbar vertebrae; kyphoscoliosis

    • deossification of vertebrae

    • small iliac wings; late fusion of iliac crests

    • android pelvic inlet with narrowed pubic arch + small sacrosciatic notches

  • @ Chest

    • thinning of lateral aspects of clavicles

    • thinned + narrowed ribs with pseudonotching

  • @ Hand + arm

    • positive metacarpal sign = relative shortening of 3rd + 4th metacarpal

    • positive carpal sign = narrowing of scaphoid-lunate-triquetrum angle <117

    • phalangeal preponderance = length of proximal + distal phalanx exceeds length of 4th metacarpal by >3 mm

    • shortening of 2nd + 5th middle phalanx (also in Down syndrome)

    • drumstick distal phalanges = slender shaft + large distal head

    • insetting of epiphyses into bases of adjacent metaphyses (phalanges + metacarpals)

    • Madelung deformity = shortening of ulna / absence of ulnar styloid process

    • cubitus valgus = bilateral radial tilt of articular surface of trochlea

    • deossification of carpal bones

  • @ Knee

    • tibia vara = enlarged medial femoral condyle + depression of medial tibial plateau (DDx: Blount disease)

    • small exostosis-like projection from medial border of proximal tibial metaphysis

  • @ Foot

    • deossification of tarsal bones

    • shortening of 1st, 4th, and 5th metatarsals

    • pes cavus

  • US:

    • prepubertal uterus

    • nonvisualized / streaky ovaries (in complete monosomy); normal ovaries (in mosaic karyotype)

  • OB-US:

    • large nuchal cystic hygroma

    • lymphangiectasia with generalized hydrops

    • symmetrical edema of dorsum of feet

    • CHD (20%): coarctation of aorta (70%), left heart lesions

    • horseshoe kidney

P.175


Bonnevie-Ullrich Syndrome

  • = infantile form of Turner syndrome

  • (1) congenital webbed neck

  • (2) widely separated nipples

  • (3) lymphedema of hands + feet

Turret Exostosis

Cause: trauma with formation of subperiosteal hematoma

  • immobile, occasionally painful lump on dorsum of finger

  • reduced ability to flex finger (= ossified hematoma diminishes excursion of extensor tendon)

    Location: dorsum of proximal / middle phalanx of hand

  • smooth dome-shaped extracortical mass

Ulnar Collateral Ligament Tear

Cause: chronic overuse in throwing / other overhead motion (eg, tennis serving) generating increased valgus stress

  • acute onset of sharp / gradual onset of increasing pain in medial elbow

  • ulnar nerve dysfunction (40%): pain, paresthesia of forearm + in 4th and 5th digits

  • ossification within ulnar collateral ligament (UCL)

  • loose bodies

  • osteoarthritis of ulnohumeral articulation

  • osteochondritis dissecans of capitellum

  • excessive medial joint opening on stress radiographs

  • MR (coronal plane):

    • laxity / discontinuity of UCL

    • increased signal intensity of UCL + surrounding tissues

    • poor definition of ligament margins

    Rx: rest, application of ice, NSAID, exercise, steroid injections; reconstruction of ligament

Van Buchem Disease

  • = GENERALIZED CORTICAL HYPEROSTOSIS

  • = autosomal recessive disease; may be related to hyperphosphatasemia

    Cause: defect on chromosome 17

  • paralysis of facial nerve

  • auditory + ocular disturbances (in late teens secondary to foraminal encroachment)

  • increased alkaline phosphatase

    Location: skull, mandible, clavicles, ribs, long-bone diaphyses

  • symmetrical generalized sclerosis + thickening of endosteal cortex

  • obliteration of diploe

  • spinous processes thickened + sclerotic

    DDx: (1) Osteopetrosis (sclerosis of all bones, not confined to diaphyses)
    (2) Generalized hyperostosis with pachydermia (involves entire long bones, considerable pain, skin changes)
    (3) Hyperphosphatasia (infancy, widened bones but decreased cortical density)
    (4) Engelmann disease (rarely generalized, involves lower limbs)
    (5) Pyle disease (does not involve middiaphyses)
    (6) Polyostotic fibrous dysplasia (rarely symmetrically generalized, paranasal sinuses abnormal, skull involvement)
    (7) Sclerosteosis = Truswell-Hansen disease (syndactyly of 2nd + 3rd fingers, nail dysplasia)

Williams Syndrome

  • = IDIOPATHIC HYPERCALCEMIA OF INFANCY

  • peculiar elfinlike facies, dysplastic dentition

  • neonatal hypercalcemia (not in all patients)

  • mental + physical retardation

  • @ Skeletal manifestations

    • osteosclerosis (secondary to trabecular thickening)

    • dense broad zone of provisional calcification

    • radiolucent metaphyseal bands

    • dense vertebral end plates + acetabular roofs

    • bone islands in spongiosa

    • metastatic calcification

    • craniostenosis

  • @ Cardiovascular manifestations

    • supravalvular aortic stenosis (33%), aortic hypoplasia

    • valvular + peripheral pulmonary artery stenosis

    • ASD, VSD

    • stenoses of major vessels (innominate, carotids, renal arteries)

  • @ GI and GU tract:

    • colonic diverticula

    • bladder diverticula

    Prognosis: spontaneous resolution after 1 year in most
    Rx: withhold vitamin D + calcium
    DDx: Hypervitaminosis D

Wilson Disease

  • = hepatolenticular DEGENERATION

  • = autosomal recessive disease with excessive copper retention (= copper toxicosis)

    Prevalence: 1:33,000 200,000; 1:90 persons is a heterozygous carrier
    Cause: alteration of chromosome 13 resulting in inability of liver to excrete copper into bile; hypothetically due to either
    (a) lysosomal defect in hepatocytes, or
    (b) deficiency of biliary copper-binding proteins, or
    (c) persistence of fetal mode of copper metabolism, or
    (d) hepatic synthesis of high-affinity copper-binding proteins)
    Age of onset: 7 50 years; hepatic manifestations predominate in children; neuropsychiatric manifestations predominate in adolescents + adults
    Histo: macrovesicular fat deposition in hepatocytes, glycogen degeneration of hepatocyte nuclei, Kupffer cell hypertrophy
    Stage 1 asymptomatic copper accumulation in hepatocytic cytosol
    Stage 2 redistribution of copper into hepatic lysosomes + circulation from saturated hepatocytic cytosol
    (a)gradual redistribution is asymptomatic
    (b) rapid redistribution causes fulminant hepatic failure / acute intravascular hemolysis
    Stage 3 cirrhosis, neurologic, ophthalmologic, renal dysfunction may be reversible with therapy

    • P.176


  • tremor, rigidity, dysarthria, dysphagia (excessive copper deposition in lenticular region of brain)

  • intellectual impairment, emotional disturbance

  • Kayser-Fleischer ring (= green pigmentation surrounding limbus corneae) is DIAGNOSTIC

  • jaundice / portal hypertension (liver cirrhosis)

  • elevated copper concentration in serum ceruloplasmin (BEST SCREENING TEST)

  • decreased incorporation of orally administered radiolabeled copper into newly synthesized ceruloplasmin

  • Skeletal manifestations (in 2/3):

    • generalized deossification may produce pathologic fractures

  • @ Joints: shoulder (frequent), knee, hip, wrist, 2nd 4th MCP joints

    • articular symptoms in 75%: pain, stiffness, gelling of joints

    • subarticular cysts

    • premature osteoarthritis (narrowing of joint space + osteophyte formation)

    • osteochondritis dissecans

    • chondrocalcinosis

    • premature osteoarthrosis of spine, prominent Schmorl nodes, wedging of vertebrae, irregularities of vertebral plates

  • @ Liver (in children)

    • normal hepatic attenuation (fatty infiltration + copper deposition cancel each other out)

    • normal T1 relaxation time (in spite of paramagnetic effects of copper)

  • @ Brain (adolescents + adults)

    Location: basal ganglia, rarely thalamus

    • cerebral white matter atrophy

    • hypodensities, prolongation of T1 + T2

    Cx: rickets + osteomalacia (secondary to renal tubular dysfunction) in minority of patients
    Rx: life-long pharmacologic therapy with chelation agents (penicillamine / trientine / zinc); liver transplantation


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Radiology Review Manual
Radiology Review Manual (Dahnert, Radiology Review Manual)
ISBN: 0781766206
EAN: 2147483647
Year: 2004
Pages: 24
Authors: Wolfgang F Du00e4hnert
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