Diffuse histiocytic lymphoma complicating chronic lymphocytic leukemia.

Nine patients with chronic lymphocytic leukemia (CLL) who also developed diffuse histiocytic lymphoma (DH) are described. The incidence of patients with CLL developing DH was at least 3.3%. CLL existed for a median of 2 years before the diagnosis of DH. DH presented in 8 patients with abdominal symptoms and/or enlarging lymph nodes, spleen and liver. There were no consistent laboratory abnormalities associated with the onset of DH. In 4 of the patients the DH appeared to be localized. Eight of the 9 patients have died with a median survival of 2 months from the diagnosis of DH. Whether DH occurs as a result of "blastic transformation" of pre-existing CLL or is a second, unrelated malignancy is not certain. It is hypothesized that utilizing current therapies for DH might favorably influence survival.