Twelve of 110 patients (11%) with non-Hodgkin's lymphoma seen between 1975 and 1985 developed evidence of central nervous system (CNS) lymphoma. -Leptomeningeal involvement (9), focal cerebral involvement (2) and spinal cord compression (1)- The risk of CNS invasion was greatest for those with lymphoblastic and Burkitt type lymphoma, and CNS prophylaxis was clearly warranted in these subgroups. About 10% of patients with diffuse medium-sized, mixed and large cell type had CNS disease. Patints who developed CNS lymphoma largely had extranodal origin (9/12) and advanced disease at initial staging (9/12). The incidence of CNS involvement in peripheral T cell lymphoma remained to be clarified. CNS lymphoma was observed at all times during the clinical course (0∼21 months after the onset of lymphoma), but in some patients (4/12) CNS disease developed while they were in complete remission. Patients were treated with systemic chemotherapy or intrathecal methotrexate and/or whole brain irradiation. Median survival after recognition of CNS lymphoma was 7 months, and three patients are alive without symptomes for 18, 24 and 57 months respectiely. Treatment should be done by standard stherapeutic protocols according to the forms of CNS involvement.
