Tumors of Brain

Authors: Flaherty, Alice W.; Rost, Natalia S.

Title: Massachusetts General Hospital Handbook of Neurology, The, 2nd Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Adult Neurology > Tumors of Brain

Tumors of Brain

A. See also

Spinal Cord Disorders, p. 113.

B. H&P

• 1. Generalized sx: Papilledema, GI sx, fatigue, confusion.

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• 2. Focal sx: Reflect tumor. N/V suggests post. fossa or location.

• 3. HA: Worse in AM, lying flat, or with Valsalva suggests high ICP.

• 4. Seizures: In about 1/3 of pts; more common if low-grade tumor or cortical location.

C. DDx of brain tumor

Abscess, bleed, infarct, demyelination, radiation necrosis .

D. Tests

MRI + contrast, or CT + contrast if pt unstable or question of hemorrhage. See imaging of tumor, p. 182. Brain biopsy vs. resection. Consider workup for unknown primary tumor (usually CXR, mammogram, chest/abdominal CT), LP to rule out leptomeningeal spread.

E. Rx of brain tumor

See also specific tumor types, below.

• 1. Treat edema: Consider one or more of the following:

  • a. Dexamethasone: Bolus 10 mg IV, then 4 mg q6h. Taper after radiation therapy. If you suspect CNS lymphoma, try to withhold steroids until biopsy.

  • b. Fluid restrict: 1200 cc qd, no free water.

  • c. Mannitol: 50-100 g IV, then 25-50 g q6h to keep osmolality 305-310.

• 2. Neurosurgery:

  • a. Resection: Unless inaccessible, multiple foci, or very radiosensitive. Consider surgery for all posterior fossa tumors >3 cm even if there are other metastases.

  • b. Biopsy: In situations where full resection is inadvisable but a tissue diagnosis is necessary.

  • c. CSF access procedures: see p. 85. E.g., EVD or VP shunt for hydrocephalus, Ommaya reservoir for intraventricular chemotherapy.

• 3. Radiation therapy: Consider 2-3 d of steroids before beginning XRT to decrease swelling, especially in posterior fossa lesions.

• 4. Chemotherapy: Regimens vary. see p. 166 for side effects.

• 5. Seizure prophylaxis: No need to provide prophylaxis to pts who have never seized, except if there is a risk of herniation. Metastases in the cerebellum or deep subcortical areas rarely cause seizures.

F. Prevalence

• 1. Metastases: 30%-50% of all brain tumors. Presenting complaint is from a brain met in 15% of all cancer pts. 10% present with seizures.

• 2. Primary intracranial tumors: Astrocytomas (including GBM) 38%, meningiomas 18%, acoustic schwannomas 8%, oligodendrogliomas 4%, lymphomas 4%, craniopharyngiomas 1%.

G. Metastases

to CNS:

• 1. Most common source: Usually carcinoma sarcoma or lymphoma.

  • a. Intracranial metastases: Lung > breast > melanoma > renal, colorectal, lymphoma, and unknown primary. Prostate is very rare.

  • b. Dural, epidural, skull metastases: Breast, prostate.

  • c. Leptomeningeal metastases: see p. 124.

• 2. Tumors most likely to have brain metastases: Melanoma (40%).

• 3. Metastases likely to bleed: Renal, papillary thyroid, melanoma, choriocarcinoma, lung.

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• 4. Number: On MRI, only 20%-30% of mets are solitary.

  • a. Solitary metastases: Resection is usually offered. If cannot resect, consider biopsy because 10% turn out not to be mets even if the pt has another known primary.

  • b. Multiple metastases: Consider resection of the dominant, symptomatic lesion. Stereotactic radiosurgery may help small lesions.

• 5. Location: 80% are supratentorial, 15% cerebellar (50% of cerebellar metastases are pelvic/GI).

• 6. Prognosis for brain metastases:

  • a. No rx: 4-wk survival.

  • b. Steroids alone: 8 wk.

  • c. Steroids + XRT: 3-6 mo (most die of other cause).

  • d. Surgery + XRT: 10-16 mo.

H. Gliomas

Include astrocytomas, oligodendrogliomas, oligoastrocytomas, ependymomas.

• 1. Brainstem gliomas, cerebellar astrocytomas, ependymomas: Mostly pediatric; see p. 151.

• 2. Astrocytomas:

  • a. World Health Organization (WHO) grading:

    Table 34. Astrocytoma grading.

    Grade	Scan of Mass	Survival	Usual Pathol.	Treatment
    I	Post. fossa mass	Excellent	Pilocytic astro.	Surgery
    II	Nonenhanced	7-10 yr	Diffuse astro.	Surg+XRT chemo
    III	Enhanced	~2 yr	Anaplastic astro.	Surg+chemo+XRT
    IV	Enhanced	<1 yr	GBM: necrosis, vasc. prolif.	Surg+chemo+XRT

  • b. Recurrence: ~90% near original site. Some white matter spread (e.g., butterfly glioma across callosum). Metastases rare.

  • c. Rx of astrocytoma: Surgery, XRT (q.v. p. 125), alkylating agents. No longer standard to use procarbazine, CCNU, vincristine.

• 3. Oligodendrogliomas: May be grade II (low grade) or grade III (anaplastic). Often present with seizures. Often calcified. More chemosensitive than astrocytomas. 50%-70% of anaplastic lesions have loss of chromosomes 1p and 19q, which suggests increased chemosensitivity, good prognosis.

• 4. Meningiomas (20% of intracranial primaries): Arise from the arachnoid. Mostly indolent, often asymptomatic incidentalomas. Sx relate to tumor location; seizures and HA occur rarely. 8% are multiple, higher in type 1 neurofibromatosis.

  • a. DDx: Includes prostate or breast metastasis to bone.

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  • b. Scans: Light bulb enhancement, attached to meninges ( dural tail on post-gado MRI), usually extra-axial, may show peritumoral edema. Often calcified, with adjacent hyperostosis or bone erosion.

  • c. Rx: Surgery usually curative, often bloody. Often need re-op angio ( embolization) to define vascular involvement and assess venous sinus invasion or occlusion. XRT (and, increasingly, stereotactic radiosurgery for small lesions) is effective for incompletely resected tumors.

I. Pituitary tumors

• 1. H&P:

  • a. Secretory tumors: Sx of hormonal excess: Cushing's syndrome, acromegaly, or galactorrhea.

  • b. Nonsecretory tumors: Sx of mass effect: bitemporal field cuts, headache, hypopituitarism, invasion of cavernous sinus.

  • c. Pituitary apoplexy: An emergency. See sudden headache, visual deterioration, diplopia, and drowsiness. From bleed into tumor. Requires immediate surgery to preserve vision.

• 2. DDx: Suprasellar mass, pituitary infarct or apoplexy, inflammation.

• 3. Tests: MRI with gadolinium and thin cuts through sella (see p. 190), adrenal function (see p. 199), thyroid function (see p. 201), prolactin, follicle-stimulating and luteinizing hormones, estradiol in women, testosterone in men, growth hormone if there is acromegaly.

• 4. Rx:

  • a. Surgery: Usually transsphenoidal or pterional (see p. 85). Indications include apoplexy, acromegaly, Cushing's syndrome, macroadenomas, prolactinomas with PRL <500 ng/mL (chance of normalizing PRL >500 is low), or unresponsive to meds.

  • b. Medical:

    • 1) Bromocriptine:

      • a) Prolactinomas: Start 1.25-2.5 mg qd; add additional 2.5 mg qd every 3-7 d as necessary. Usual dose 5-7.5 mg qd.

      • b) Growth hormone tumors: may need more. Max. dose is 100 mg qd.

      • c) SEs: Include nausea, orthostasis, cognitive complaints, psychosis. Minimize these by giving qhs with food.

    • 2) Cabergoline: At least as effective as bromocriptine in lowering prolactin levels and shrinking tumor, with substantially fewer side effects. Long half-life allows twice-weekly dosing. Start 0.25 mg 2 /wk, incr. monthly by 0.25 mg 2 /wk based on prolactin levels. Max. dose is 1 mg 2 /wk.

    • 3) Octreotide: For growth hormone secreting tumors. Very expensive. SEs include GI disturbance, gallstones. Dosing varies with GH levels.

    • 4) Hormone replacement therapy: Adrenal, thyroid, or sex hormones when necessary.

  • c. XRT: Not routinely used. Side effects include hypopituitarism, optic nerve damage, lethargy, diplopia, and pituitary apoplexy.

J. Vestibular schwannomas

Formerly inaccurately called acoustic neuromas and acoustic neurinomas. Benign, cerebellopontine angle tumors.

• 1. H&P: First symptom is usually gradual unilateral hearing loss. Also common are tinnitus, vertigo, imbalance; later headache, facial numbness, weakness, or diplopia. Look for signs of

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  neurofibromatosis. Bilateral vestibular schwannomas are pathognomonic for NF2.

• 2. DDx: Meningioma (often nerve V involvement before VII, calcification on CT) or other tumor.

• 3. Tests: MRI with thin cuts through internal auditory meatus, or CT with contrast. MRI usually shows a round or ovoid enhancing mass in the IAM. Audiological testing may help establish a baseline for postsurgical comparison.

• 4. Rx: Goal is to prevent complications (esp. hearing loss). Surgery, stereotactic radiosurgery, and fractionated stereotactic radiotherapy appear equally safe and effective.

  • a. CSF leak rx: 3-5 d of lumbar drainage to allow healing.

  • b. Facial nerve dysfunction rx: Gold weight (to maintain eye closure) or hypoglossal-facial anastomosis (to restore facial tone).

Table 35. Management of vestibular schwannomas.

Tumor	Good Surgical Candidate	Poor Surgical Candidate
<3 cm	If good hearing, surgery If no hearing, observation1	Observation1
>3 cm	Surgery	Surgery or radiosurgery
1Observation = repeat neuro exam and imaging q 6 mo 2 yr, then annually if sta-ble. If exam deteriorates or growth is >2 mm/yr, consider surgery or radiosurgery.

K. Primary CNS lymphomas

Rare, but much more common in AIDS. Sx relate to location.

• 1. DDx: In HIV, toxo is primary concern. If there are multiple lesions, give 2 wk of empiric toxo therapy and look for response before bx. In immunocompetent host, biopsy is necessary for dx.

• 2. Tests: MRI with gado.

  • a. Immunocompetent: A homogeneously enhancing mass in white matter or basal ganglia. 20%-40% multifocal.

  • b. AIDS: Often rim enhanced. Up to 70% multifocal.

• 3. Rx/prognosis: Months if untreated. Chemo regimens are mostly methotrexate based, with 5-year median survival. XRT may be provided after chemo. No role for surgery. Steroids cause temporary (sometimes dramatic) regression.

L. Leptomeningeal metastases

Can be the presenting problem. Most common in leukemia, lymphoma, breast cancer, lung cancer.

• 1. H&P: Synchronous signs or sx at multiple sites in brain, cranial nerves, or spinal cord. Often back pain or postural headache.

• 2. Tests:

  • a. CT or MRI: To r/o mass before LP. Communicating hydrocephalus suggests leptomeningeal dz. Contrast may show meningeal enhancement.

  • b. LP: Do cytology for malignant cells (80% sensitive after 3 LPs). Send at least 3 cc. Cells degrade quickly; do not let them sit.

• 3. Rx: Depends on primary tumor. Most breast cancers and lymphomas respond, as do about 30% of lung cancers and 20% of melanomas. Untreated pts. usually die within weeks.

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  • a. XRT: Irradiate symptomatic areas. Often given with dexamethasone.

  • b. Chemotherapy: Usually intrathecal methotrexate. Consider Ommaya reservoir.

  • c. Ventriculoperitoneal shunt: For symptomatic hydrocephalus.