Peripheral T-cell lymphoma with Reed-Sternberg-like cells of B-cell phenotype and genotype associated with Epstein-Barr virus infection

We report three cases of nodal peripheral T-cell lymphoma (PTCL) with Reed- Sternberg-like (RS-Like) cells of B-cell pheno- and/or genotype. Histologic analysis in all cases revealed diffuse nodal effacement by atypical lympho id cells of variable size. Two of the three cases had features of angioimmu noblastic T-cell lymphoma (AILT). Large mononuclear and binucleated cells w ith prominent eosinophilic nucleoli and abundant cytoplasm resembling class ic RS cells and mononuclear variants were scattered throughout all biopsies . The lymphoma cells in the three cases were of T-cell lineage (CD3+, CD43, and CD45RO+). The RS-like cells from all cases were CD30 and CD15 positiv e. In contrast to the neoplastic T cells, the RS-like cells lacked all T-ce ll markers and in two cases were positive for CD20. Epstein-Barr virus (EBV ) latent membrane protein 1 (LMP1) and EBER 1 (2/2) were detected in the RS -like cells in all cases. The neoplastic T cells were negative for EBV. Pol ymerase chain reaction (PCR) analysis demonstrated clonal rearrangements of the T-cell receptor gamma chain gene in the three cases. PCR analysis of m icrodissected RS-like cells for immunoglobulin heavy chain gene rearrangeme nts in cases 1 and 3 showed an oligoclonal pattern. The presence of RS-like cells in PTCL represents a diagnostic pitfall, because in one case this ob servation led to a misdiagnosis of Hodgkin's disease (HD), The oligoclonal expansion of EBV-infected cells may be related to underlying immunodeficien cy associated with T-cell lymphomas and AILT in particular. This phenomenon may provide the basis for some cases of Hodgkin's disease after T-cell lym phomas and suggests that they are clonally unrelated neoplasms. The express ion of LMP1 appears to be crucial for the immunophenotype and probably for the morphology of the RS and RS-like cells appearing in diverse lymphoid ma lignancies, including HD, chronic lymphocytic leukemia, and PTCL.