Chronic myelomonocytic leukemia coexisting with B-cell chronic lymphocytic leukemia.

Coexistence of B-cell chronic lymphocytic leukemia (B-CLL) and chronic myelomonocytic leukemia (CMML) is an unusal event, and to our knowledge, only four such cases have been reported in the literature. We report a 68-year-old white woman in whom these two diseases were diagnosed concomitantly. The diagnosis was made on the basis of peripheral blood count, morphology and immunophenotyping, and bone marrow cytology and histology. Interphase FISH analysis detected a 13q14.3 deletion in lymphocytes nuclei and no such abnormality in monocytes nuclei. The PCR analysis of IgH gene rearrangement in the bone marrow, as well as the peripheral blood lymphocytes, showed two different monoclonal IgH configurations as the result of biallelic clonal rearrangement of IgH genes suggesting an origin of lymphocytes from B-cell progenitors. The patient was originally treated with prednisone 1 mg/kg/day because of progressive significant thrombocytopenia, without improvement. Subsequently, she received one course of cladribine (2-CdA). Significant reduction of lymphocytes in the peripheral blood was observed. However, rapid increase of monocytes was seen shortly after the 2-CdA treatment. Subsequently, she received hydroxyurea (1.5 g/day) without hematological improvement. The patient died in January 2003, three months after diagnosis because of progression of both leukemias and associated pneumonia. Possible etiopathogenic relationship between both disorders is discussed.