RESUMEN
Abstract: It is difficult how to manage acute undifferentiated leukemia in daily practice, but generally, hand mirror morphology provides ease to treat these patients. Thirty-nine years old male patient was admitted to with the complaints of echymosis, and pain at his left buttock due to an intramuscular injection for the treatment of previously diagnosed of the lower respiratory infection. Peripheral blood smear revealed >%50 blasts cells with a moderate nuclear: cytoplasmic ratio and one or more nucleoli. The blast cells showed a hand-mirror morphology and not harboring auer rods. According to the flow cytometric analysis the blastic cells do not represent to be originated from myeloid or lymphoid origin, because the cells harboring both of two cell lineages. AML-like therapy was commenced based on the positive myeloid markers including CD117 and CD135. Even though hand mirror morphology of the blasts usually demonstrates the lymphoid origin and the patients are treated as ALL like therapy, myeloid blasts rarely represents the same morphology, as was in our patient.