RESUMEN
Primary central nervous system lymphomas (PCNSLs) are a rare form of non-Hodgkin's lymphoma which arise within and remain confined primarily to the central nervous system (CNS). They generally account for 1-2% of all primary brain tumors and are reported to be on the rise due to the Acquired Immune Deficiency Syndrome (AIDS) epidemic. AIMS AND OBJECTIVES: To study the clinicopathological and immunophenotypic characteristics of PCNSLs and look for any differences in PCNSLs reported in India from those in other countries. MATERIALS AND METHODS: All cases of PCNSLs between January 1998 and December 2006 were reviewed. Presence of lymphadenopathy, organomegaly and bone marrow study was done to exclude the possibility of secondary involvement by lymphoma. The diagnosis was confirmed by histopathology with Hematoxylin and Eosin and reticulin stains. Immunohistochemistry (IHC) with leucocyte common antigen (LCA), CD 20 and CD 3 was performed on available blocks. The immune status was evaluated by clinical examination and human immunodeficiency virus (HIV) serology (since 1996). RESULTS: In a 19-year study period, there were 56 patients of PCNSLs, accounting for 1.07% of all intracranial neoplasms. The patients ranged from 10-75 years of age with a median age of 42 years. Barring one patient who was HIV positive, all the others were immunocompetent. All cases were diffuse large cell lymphomas on histopathology. IHC with LCA and CD 20 revealed positivity in 100% and 86.4% cases respectively. There was a single case of CD 3 positive T-cell lymphoma. In the present study, PCNSLs occurred in young immunocompetent patients and majority were diffuse large B cell lymphomas.