Example morphology and immunophenotype of acute promyelocytic leukemia

(A) Blasts in the typical variant of acute promyelocytic leukemia (APL) showing prominent cytoplasmic granules and multiple Auer rods. (B) Blasts in the microgranular variant of APL with bi-lobed or “butterfly-shaped” nuclei. (C) By flow cytometry, the blasts in APL typically show increased side-scatter and are positive for CD117 but negative for CD34 and HLA-DR.