AIDS-RELATED PRIMARY BRAIN LYMPHOMAS - HISTOPATHOLOGIC AND IMMUNOHISTOCHEMICAL STUDY OF 51 CASES

Fifty-one cases of acquired immunodeficiency syndrome (AIDS)-related p rimary brain lymphomas (AR-PBL) ere investigated for clinical characte ristics; human immunodeficiency virus (HIV)-associated disorders; hist opathologic features; immunophenotype; Epstein-Barr virus (EBV) infect ion; and, when frozen tissue was available, oncogene rearrangements. A R-PBL occurred late in the course of AIDS and were usually associated with other systemic or cerebral disorders and with a low level of CD4 lymphocytes. All cases were high grade lymphomas according to the Work ing Formulation or updated Kiel classification, and often displayed a multifocal pattern. Thirty cases were classified as immunoblastic with plasmacytic differentiation, 18 cases were large cell lymphomas with an immunoblastic component or centroblastic polymorphic lymphomas, and 2 were small noncleaved non-Burkitt lymphomas (Working Formulation). This latter category is classified as Burkitt's-like lymphoma in the R EAL nomenclature. One case could not be classified because of necrosis . AR-PBL showed a high level expression of activation and adhesion mol ecules. The presence of EBV was detected in most cases, and, when PCR was used, this was a constant finding. bcl-2 oncoprotein and latent me mbrane protein-1 (LMP-1) were strongly expressed. None of the tested c ases expressed p53, or were rearranged for bcl-2 or c-myc oncogenes. T his study confirms the immunophenotypic specificity of AR-PEL, which m ay reflect the special immune status of the brain. Copyright (C) 1997 by W.B. Saunders Company.