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• In the last 10 years, there has been a large increase in the diagnosis of primary CNS

lymphomas, particularly in patients with autoimmunodeficiency syndrome (AIDS).

• Most CNS lymphomas presenting in the CNS are B-cell lymphomas. Histologically,

most tumors are intermediate- or high-grade lymphomas (Working Formulation).

• Immunohistochemical analysis is performed to confirm monoclonality and B versus T

cell type.

• Stereotactic biopsy is sufficient for tissue diagnosis, and obviates the morbidity of open craniotomy.

• Staging investigations include an ophthalmologic assessment to rule out ocular

involvement, CSF cytology, complete blood cell count, Epstein-Barr virus and human immunodeficiency virus (HIV) serology, and contrast-enhanced MRI or CT of the brain.

• Systemic staging (CT of chest and abdomen, bone marrow biopsy) is rarely positive

in patients with typical findings of CNS lymphoma, but should be performed if signs or symptoms suggestive of systemic involvement are present (night sweats, fever, or lymphadenopathy).

• The extent of surgical resection does not correlate with survival.

• Treatment with corticosteroids dramatically improves symptoms in most cases, but

response is temporary; patients usually relapse within 6 months.

• For nonimmunosuppressed patients, whole-brain irradiation (40 to 50 Gy), with or

without local boost to the primary tumor (to 60 to 65 Gy), is suggested. The posterior orbits are included in the whole-brain fields. In patients with ocular involvement, the whole eye is treated to 30 to 40 Gy, with shielding of the anterior chamber and lacrimal apparatus after this dose. The frequent association of ocular lymphoma with synchronous or metachronous CNS lymphoma led to the recommendation by some authors of prophylactic brain irradiation in all patients. Craniospinal irradiation is suggested for patients with documented CSF involvement, but intrathecal chemotherapy may be equally efficacious and less toxic.

• For immunosuppressed patients, modification of the irradiation dose and schedule

immunosuppression, HIV-positive patients with no other AIDS-defining diagnoses, CD4 lymphocyte counts greater than 200) should receive standard treatment; those with poor prognostic features (low Karnofsky performance status, CD4 count less than 200, advanced AIDS) may be treated with an abbreviated course of irradiation (36 to 40 Gy).

• Although irradiation is effective in inducing temporary responses, the high relapse

rate has led to the use of combined chemotherapy (cyclophosphamide, doxorubicin,

vincristine, and prednisone or dexamethasone) and irradiation. Impressive results

have been obtained with intrathecal and intravenous methotrexate followed by cranial

irradiation and intravenous cytarabine (Ara-C).

Meningioma

• Meningioma occurs in the cerebral convexities, falx cerebri, tentorium cerebelli,

cerebellopontine angle, and sphenoid ridge.

• Meningioma typically presents as a problem of local control, with local recurrence

being the most troublesome aspect.

• Malignant varieties with invasive growth and aggressive behavior occasionally occur,

especially among recurrent tumors.

• Location of the lesion, extent of surgical resection, and histopathologic features of the tumor (benign or malignant) are the most important prognostic factors.

• Treatment of choice for benign meningioma is complete surgical resection, if it can be

accomplished with low morbidity.

• Complete resection may be difficult without significant morbidity in base of skull, cerebellopontine angle, or cavernous sinus meningioma. For these patients, conservative subtotal resection followed by postoperative irradiation, rather than aggressive base of skull resection, may give good local control with decreased morbidity (1,35).

• Postoperative irradiation doses of 50 to 54 Gy in 1.8- to 2.0-Gy fractions are usually

recommended for patients with subtotally excised, unresectable, or recurrent benign meningioma (11).

• Target volume is generally restricted to a 2-cm margin beyond the tumor volume

defined by CT or MRI scan and modified by the neurosurgeon's description of the location of residual tumor; more generous margins may be necessary for extensive skull base meningiomas (25). Postoperative irradiation after maximal resection is recommended for all malignant meningiomas; recurrence after surgery alone is high (50% to 100%), even with complete surgical resection. The target volume for malignant meningioma is more generous (3-cm margin) than that used for benign lesions; recommended dose is 60 Gy in 1.8- to 2.0-Gy fractions (11).

• Multiple fields with wedge filters or rotational fields and 3-D conformal techniques are used to maximally spare normal brain tissue.

• Radiosurgery has been used as the sole modality for selected patients with smaller

meningiomas (16).

• For elderly patients with comorbidities, expectant management with deferred

irradiation may be appropriate for small asymptomatic lesions or even after subtotal resection.

• Chemotherapy is not used as standard therapy, and the efficacy of antiprogesterone

agents has not been demonstrated.

Craniopharyngioma

• Craniopharyngioma is a benign neoplasm of the suprasellar region.

• It is more common in children but is occasionally seen in adults, who typically present

with craniopharyngioma early and with visual symptoms (quadrantopsia, hemianopia, or even blindness).

• The cystic nature of craniopharyngioma is usually evident on CT and MRI scans;

calcifications in the wall are common.

• Complete surgical resection can result in long-term local control and cure; some

• Partial resection or cyst aspiration and biopsy rapidly relieve local compressive symptoms and have less operative morbidity, but are associated with eventual tumor

progression in most cases. Recurrence is associated with worse prognosis (41).

• Irradiation combined with limited surgical procedures (partial resection or aspiration plus biopsy) minimizes the potential morbidity of aggressive resections (20,41).

• Typical doses are 50 to 54 Gy in 1.8-Gy fractions in 6 weeks, delivered to the

preoperative tumor volume with a 1.5-cm margin. Techniques used include three fields (opposing lateral and frontal/vertex portals) or 3-D conformal irradiation.

• In patients with compressive symptoms, surgical decompression before irradiation is

essential, as the tumor typically responds slowly to radiation therapy; in some patients radiation-induced edema can worsen compressive symptoms.