Richter's transformation of chronic lymphocytic leukemia with Hodgkin's-like cells is associated with Epstein-Barr virus infection.

The appearance of a high-grade lymphoma in the setting of B-cell chronic lymphocytic leukemia (CLL) is termed Richter's syndrome. Usually the high-grade component is a monomorphous, large cell lymphoma, but occasionally the high-grade component takes the form of Hodgkin's disease or a Hodgkin's-like lymphoma. Although Richter's syndrome is thought to represent clonal evolution of the underlying B-cell neoplasm in most cases, such a progression is difficult to explain when the high-grade component is Hodgkin's disease. We report two cases of Richter's syndrome in which the large cells had a morphology consistent with Reed-Sternberg cells and were found in a background of CLL. The large cells in both cases expressed the CD15 and CD30 antigens in a pattern characteristic of Reed-Sternberg cells, and the large cells in one case also expressed monotypic cytoplasmic immunoglobulin of the same type as that expressed by the underlying CLL. In both cases, Southern blot analysis of DNA from lymph nodes that contained both CLL and the Hodgkin's-like component showed single immunoglobulin gene rearrangements. Using the polymerase chain reaction, we found Epstein-Barr virus DNA in lymph nodes from both cases, and in peripheral blood lymphoid cells from one case 4 yr before the onset of Richter's syndrome. Immunoperoxidase staining showed expression of EBV latent membrane protein only in the Reed-Sternberg-like cells.(ABSTRACT TRUNCATED AT 250 WORDS)