[Richter's syndrome with identical immunoglobulin gene rearrangements].

A 75-year-old man was admitted to our hospital because of hepatosplenomegaly, generalized lymphadenopathy and lymphocytosis in February, 1989. The leukocyte counts were 93,200/microliters with 95% small lymphocytes which expressed surface membrane immunoglobulin (SmIg) M, D and kappa. Histological finding of the cervical lymph node was diffuse small cell lymphoma. A diagnosis of chronic lymphocytic leukemia (CLL) was made. He was followed up without chemotherapy. In January, 1990, he was re-admitted because of progressively enlarged lymph nodes and increased white blood cell counts, up to 183,200/microliters with 98% lymphocytes. He was treated with vincristine, cyclophosphamide, prednisolone. The leukocyte counts decreased to 5,000/microliters and lymph node swelling decreased in size. In April, 1990, generalized lymphadenopathy re-appeared. The biopsied lymph node specimen showed diffuse large cell non-Hodgkin lymphoma (NHL-DL). The lymph node cells were found to express SmIgM and kappa. The diagnosis of Richter's syndrome was made. DNA analysis using Southern blot method revealed identical immunoglobulin heavy and kappa chain gene rearrangements in the two neoplasms. These findings suggest that the CLL cells and the NHL-DL cells originate from the same clone in this case.