Hand-mirror variant of microgranular acute promyelocytic leukemia

We report a case of microgranular acute promyelocytic leukemia (APL, M3 V) presenting with the typical features of disseminated intravascular coagulopathy and cells with irregular, folded, or bilobed nuclei with occasional intracytoplasmic multiple Auer rods in the peripheral blood. A cytogenetic study of the bone marrow and blood showed translocation between chromosomes 15 and 17, characteristic of APL. The flow cytometric study also confirmed this diagnosis. The unusual feature in this case is the existence of 80% hand-mirror cells, which also contain multiple Auer rods, in the bone marrow. The hand-mirror variant of acute leukemia has been frequently encountered in acute lymphoblastic leukemia, but documented in only six cases of acute myelogenous leukemia, including the FAB groups of M1, M2, M4, and M5. This patient is, to our knowledge, the first reported case of a hand-mirror variant in microgranular APL. The mechanism of hand-mirror cell formation and its prognostic implication are discussed.