Lymphomas occurring specifically in HIV-infected patients: from pathogenesis to pathology.

Lymphomas that develop in HIV positive patients are predominantly aggressive B-cell malignancies. The most common HIV-associated lymphomas are Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). Lymphomas that occur specifically in HIV positive patients include primary effusion lymphoma (PEL) and its solid variants, plasmablastic lymphoma of the oral cavity type and lymphoma associated with Kaposi sarcoma herpesvirus (KSHV)-related multicentric Castleman disease. These lymphomas, together with BL and immunoblastic lymphoma subtypes with plasmacytoid differentiation, carry Epstein-Barr virus (EBV) infection and display a phenotype related to plasma cells. Globally, EBV is identified in the neoplastic cells of approximately 40% of HIV-associated lymphomas, but the detection of EBV varies considerably with the site of presentation and the histological subtype. EBV infection occurs in 80-100% of primary central nervous system lymphomas and PELs, 80% of DLBCLs with immunoblastic-plasmacytoid features, and 30-50% of BL-plasmacytoid. KSHV is specifically associated with PEL, which usually occurs in a setting of profound immunosuppression. Current knowledge about HIV-associated lymphomas can be summarized as follows: (1) lymphomas specifically occurring in patients with HIV infection are closely linked to other viral diseases; (2) most of these lymphomas exhibit plasmablastic differentiation.