The diagnostic profile of rare acute myelomegakaryoblastic leukemia.

Acute myelomagakaryocytic leukemia is a diagnostic and therapeutic challenge owing to its heterogeneity and overlapping features with other types of acute leukemia. In order to build a diagnostic profile, we analyzed the biological, clinical and hematologic characteristics of acute myelomagakaryocytic leukemia. We found that, in three patients diagnosed with acute myelomagakaryocytic leukemia, there were two types of leukemia cells. One type was myeloblastic with positive peroxidase (POX) stainig and the expression of antigens CD13 and CD33. The other type was megakaryoblastic with negative POX staining and the expression of antigens CD36, CD41, CD42a and CD61. Three patients displayed the same cytogenetic abnormality, a (9: 22) translocation. Among the three patients with RT-PCR, two patients displayed BCR-ABL fusion gene amplification and one patient showed a previously undescribed OTT-MAL fusion gene amplification.