Richter's syndrome with two different B-cell clones.

The diagnoses of chronic lymphocytic leukemia (CLL) in prolymphocytic transformation, and diffuse large cell lymphoma (DLC), were made simultaneously in a 71-year-old man. The DLC showed mu lambda surface immunoglobulin. The CLL in a lymph node and in the peripheral blood showed mu kappa. Immunoglobulin gene DNA analysis confirmed the presence of different rearrangements in the heavy and light chain genes of the CLL and DLC. Other cases reported of Richter's syndrome are discussed, and it is concluded that there may be two types of Richter's syndrome, those arising from transformation of a single clone, and those occurring from expansion of two morphologically and immunologically distinct clones, as, it is believed, is the case in this patient.