AIDS-RELATED BURKITTS-LYMPHOMA - MORPHOLOGIC AND IMMUNOPHENOTYPIC STUDY OF BIOPSY SPECIMENS

In patients infected with HIV, high-grade B-cell non-Hodgkin's lymphom as (NHL), including the small noncleaved cell (SNCC) category, exhibit pleomorphic features, which makes precise definition difficult, Sixty -nine pathologic specimens with HIV-related systemic lymphomas, includ ing 42 SNCC, 20 immunoblastic lymphomas (IBL), and 7 cases with featur es ''intermediate'' between SNCC and IBL were morphologically and immu nophenotypically investigated. The host immune status was also analyze d in 57 of 69 patients. In 29 representative SNCC lymphomas, in 9 IBL cases, and an additional 3 intermediate lymphomas, both p53 protein ov erexpression and the association of Epstein-Barr virus (EBV) genetic i nformation were assessed. Small noncleaved cell lymphomas included tum ors exhibiting features of the 2 established subtypes (27 Burkitt's an d 15 non-Burkitt's). In the seven intermediate cases, cells showed fea tures intermediate between SNCC with plasmablastic differentiation and immunoblasts plasmacytoid. Immunoblast-like cells were also present, p53 protein overexpression and EBV association were found in a proport ion of SNCC (14 of 29; 7 of 29) and intermediate (3 of 3; 2 of 3) lymp homas. Conversely, IBL cases were consistently p53 negative, but showe d a high EBV association (7 of 9), All the evaluated patients with int ermediate lymphomas had a considerably lower mean (76.6 per mm(3) +/- 77.4 SD) and median (54 per mm(3)) number of CD4+ lymphocyte count tha n SNCC patients (mean 227.9 per mm(3) +/- 186.9 SD, median 193 per mm( 3)), thus mirroring IBL patients (mean 95.3 per mm(3) +/- 82.8 SD, med ian 81 per mm(3)). All data provide evidence that lymphomas showing in termediate features constitute a distinct subgroup from either SNCC or IBL.