Acute minimally differentiated myeloid leukemia (M0) with inv(3)(q21q26).

We describe a 55-year-old Japanese man with acute minimally differentiated myeloid leukemia (M0) with an inversion in the long arm of chromosome 3, i.e., inv(3)(q21q26). Patients with this chromosomal abnormality usually show normal or elevated platelet counts. However, our case had a low platelet count with megakaryocytic dysplasia at diagnosis. Furthermore, the 3q21q26 aberration is generally detected in patients with acute myelogenous leukemia (AML) or myelodysplastic syndrome. To the best of our knowledge, it has also been reported in two cases of AML-M0 with 3q21q26 and this is the third case of AML-M0 with 3q21q26. Thus it is suggested that there is some relationship between this type of karyotype abnormality and leukemogenesis and/or thrombopoiesis.