Unusual blasts with basophilic granules in 2 cases of de novo acute myeloid leukemia with inv3(q21q26.2) and monosomy 7 and coexpression of CD2 and CD31.

Acute myeloid leukemia with inv3(q21q26.2)/t(3,3)(q21;q26.2) is a subtype of acute myeloid leukemia associated with significant dysmyelopoiesis and a poor prognosis. In more than a half of the cases, there is also monosomy 7. We present 2 young male patients with de novo acute myeloid leukemia with inversion 3 and monosomy 7 who had significant morphologic and immunophenotypical similarities. Both patients had circulating subsets of blasts with unusual intracytoplasmic basophilic granules and prominent bone marrow dysmegakaryopoiesis. The leukemic myeloid blasts were negative for myeloperoxidase and had aberrant coexpression of CD2 and CD31. Despite their morphologic and immunophenotypical similarities, only 1 of the patients achieved remission and remained free of disease 24 months after bone marrow transplant. The younger patient, who had also increased hemoglobin F and an associated FLT3 D835 variant, had an acute myeloid leukemia refractory to chemotherapy and died 4 months after his diagnosis.