Chronic lymphocytic leukemia coexisting with chronic myelomonocytic leukemia

A case with coexisting chronic lymphocytic leukemia (CLL) and chronic myelomonocytic leukemia (CMML) is described. A 74-year-old man with a typical B-CLL also showed sustained peripheral blood and bone marrow monocytosis. Typical myelodysplastic changes and monosomy 7 were also found. Cytographic and immunophenotypic analysis confirmed the presence of two distinct cell populations, i.e., lymphoid and monocytoid. Both malignancies presented an extraordinarily benign prognosis. It remains uncertain whether monocytosis was either the expression of a distinct myelomonocytic clone or the progeny of a B/monocytic bipotential precursor able to feed both leukemic phenotypes.