Histologically discordant lymphomas with B-cell and T-cell components.

We describe the clinical, histologic, immunophenotypic, and genotypic features of five cases of histologically discordant lymphomas with B-cell and T-cell components. Three patients presented with B-cell lymphoma; T-cell lymphoma subsequently developed. One patient presented with T-cell lymphoma; B-cell lymphoma subsequently developed. One patient presented with synchronous B-cell and T-cell lymphomas. There were three men and two women. The median age at the initial diagnosis of lymphoma was 66 years. The mean interval between the development of the two lymphomas was 83 months. All patients died of disease. The mean survival was 96 months after the initial diagnosis of lymphoma and 14 months after the diagnosis of the histologically discordant lymphoma. Epstein-Barr virus was found in two cases--the B-cell lymphoma in the patient who presented with synchronous lymphomas, and the subsequent T-cell lymphoma in one of the patients who presented with B-cell lymphoma. Based on the results of immunophenotypic and genotypic analyses, these cases likely represent the occurrence of two distinct lymphoid neoplasms rather than histologic progression of the same neoplastic clone. Furthermore, a subset of these cases are Epstein-Barr virus-associated.