B-cell chronic lymphocytic leukemia followed by high grade T-cell lymphoma. An unusual variant of Richter's syndrome.

A 70-year-old woman with a 2-year history of B-cell chronic lymphocytic leukemia (CLL) developed headache, fever, chills, and weakness. Bone marrow examination revealed both CLL and large cell immunoblastic lymphoma (Richter's syndrome). As expected, the CLL was of B-cell lineage. The neoplasm expressed low-density monotypic IgM lambda, the pan-B-cell antigens CD19, CD20, and CDw75, and the CD5 and CD43 antigens. The large cell immunoblastic lymphoma was of T-cell lineage, positive for the CD45RB, CD3, CD45RO, and CD43 antigens, and negative for the CD20 and CDw75 antigens. Both neoplastic components were negative for Epstein-Barr virus RNA and latent membrane protein. Although 3% to 5% of patients with B-cell CLL may develop higher-grade lymphoma, usually the lymphoma is of B-cell lineage and often represents a histologic manifestation of clonal evolution. Less commonly, B-CLL patients may develop transformation to a higher grade tumor that resembles Hodgkin's disease. Both the usual form of Richter's syndrome and particularly the Hodgkin's variant of Richter's syndrome may be associated with Epstein-Barr virus. Patients with B-cell CLL rarely develop a higher grade lymphoma of T-cell lineage. To our knowledge, only one other example has been reported in the literature. Epstein-Barr virus was not associated with either neoplasm in this case.