Acute promyelocytic leukemia (APL) is a rare subtype of acute myeloid leukemia (AML) characterized by consistent clinical, morphologic, and genetic features. According to the FAB classification APL is designated as"M3 leukemia" and assigned to the WHO defined type of AML with recurrent cytogenetic abnormalities, "acute promyelocytic leukemia with t(15;17)(q22;q12), (PML/RARα) and variants".