Microgranular Acute Promyelocytic Leukemia Diagnosed by Flow Cytometry

Abstract

To the Editor: The rare microgranular variant of hypergranular acute promyelocytic leukemia may be morphologically confused with other types of acute nonlymphocytic leukemia.^{1 , 2} Although both forms are clinically similar and are associated with life-threatening diffuse intravascular coagulation, they differ morphologically. The coarse primary granules characteristic of the hypergranular form are too small to detect by light microscopy of most cells of the microgranular leukemia. Also, the nuclei of the cells of the microgranular type are usually bilobed, reniform, or folded, thus resembling nuclei of monocytes. These monocytic features may lead to an erroneous diagnosis of myelomonocytic or monocytic leukemia, which . . .