Acute myelomonocytic leukemia (AML-M4) and translocation t(6;9)(p23);q34): two additional patients with prominent myelodysplasia.

Two patients with acute myelomonocytic leukemia (AML-M4) and a specific chromosomal translocation t(6;9)(p23;q34) are reported and compared to 21 AML patients with the same translocation collected from the literature. Our observation suggest that AML with t(6;9)(p23;q34) is characterized by myelodysplasia, basophilia, and a variety of blast cell morphologies (M1, M2, M4) with a greater proportion of the cases than previously appreciated being examples of acute myelomonocytic leukemia (AML-M4). The consistent association of myelodysplasia provokes the proposal that this subtype of de novo AML is a result of an acute stem cell disorder. The poor outcome with standard AML chemotherapy experienced in this group of relatively young patients necessitates consideration of alternative therapeutic strategies such as early bone marrow transplantation.