Acute myeloid leukemia with abnormal bone marrow eosinophils inv(16)(p13q22) or t(16;16)(p13;q22)

A rare acute myeloid leukemia (AML) with recurrent genetic anomaly disorder characterized by an inv(16)(p13q22) or t(16;16)(p13;q22) cytogenic abnormality, which generates a CBFB-MYH11 fusion gene, presenting with typical morphologic features of AML as well as abnormal bone marrow eosinophils (seen in all stages of maturation with no significant signs of maturation arrest). Myeloid sarcoma and involvement of the central nervous system is relatively common. Cytology reveals myeloblasts, a significant monocytic component and variable numbers of immature eosinophils with atypical purple-violet granules in addition to eosinophilic granules. Presence of the fusion gene is sufficent for diagnosis irrespective of blast count.