AIDS-related Burkitt's lymphoma: Morphologic and immunophenotypic study of biopsy specimens

In patients infected with HIV, high-grade B-cell non-Hodgkin's lymphomas (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, including 42 SNCC, 20 immunoblastic lymphomas (IBL), and 7 cases with features 'intermediate' between SNCC and IBL were morphologically and immunophenotypically investigated. The host immune status was also analyzed in 57 of 69 patients. In 29 representative SNCC lymphomas, in 9 IBL cases, and an additional 3 intermediate lymphomas, both p53 protein overexpression and the association of Epstein-Barr virus (EBV) genetic information were assessed. Small noncleaved cell lymphomas included tumors exhibiting features of the 2 established subtypes (27 Burkitt's and 15 non-Burkitt's). In the seven intermediate cases, cells showed features 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 proportion of SNCC (14 of 29; 7 of 29) and intermediate (3 of 3; 2 of 3) lymphomas. Conversely, IBL cases were consistently p53 negative, but showed a high EBV association (7 of 9). All the evaluated patients with intermediate lymphomas had a considerably lower mean (76.6 per mm³ ± 77.4 SD) and median (54 per mm³) number of CD4+ lymphocyte count than SNCC patients (mean 227.9 per mm³ ± 186.9 SD, median 193 per mm³), thus mirroring IBL patients (mean 95.3 per mm³ ± 82.8 SD, median 81 per mm³). All data provide evidence that lymphomas showing intermediate features constitute a distinct subgroup from either SNCC or IBL.