Chronic myelomonocytic leukemia with trisomy 8 and a related clone with trisomy 8 and t(15;17).

We describe a patient with chronic myelomonocytic leukemia who showed trisomy 8 in 100% of his bone marrow metaphases. Of interest was the finding that 20% of the Giemsa-banded metaphases also showed t(15;17)(q22;q21), with breakpoints indistinguishable from those seen in cases of acute progranulocytic leukemia (APL). The patient showed no morphologic or clinical evidence of APL, and he died after 6 months, with no evidence that the disease had progressed to acute leukemia. Although cytogenetically the breakpoints appeared to be the same as those in APL, we suspect that this patient's translocation may have differed at the molecular level from the t(15;17) commonly seen in APL.