Primary lymphoma of the central nervous system: a clinicopathologic analysis of 26 cases.

We analyzed 26 cases of primary lymphoma of the central nervous system. There were 14 males and 12 females ranging in age from 5-76 years (median age 51 years, mean age 50.2 years). None had received organ transplantation or immunosuppressive therapy. The most common presenting symptoms were headache, mental changes, nausea, vomiting, and convulsions. The main neurological findings were hemiparesis, papilledema, visual field defects, and cranial nerve palsies. The most common finding in the cerebrospinal fluid (CSF) was high protein content; CSF cytology was positive in only one case. Computerized tomography was done in 14 cases; all showed a contrast-enhancing lesion. Angiography generally revealed an avascular mass. The most common location above tentorium was the frontal lobe; in four cases the tumor was infratentorial (cerebellum, 3 cases). In five cases there was diffuse involvement of the brain; all had severe dementia and diagnosis was not made until the autopsy. Histologically, the most common type was diffuse histiocytic or immunoblastic lymphoma according to Rappaport and the Working Formulation classification respectively. Radiation therapy alone in five patients gave a median survival of 17 months. Five patients received radiation and chemotherapy, and median survival was 16 months. Two patients developed ocular lymphoma 8 and 36 months later that was treated by radiation.