The authors describe the case of a 71-year-old patient with acute megakaryocytic leukemia (AML-M7) who was successfully treated with low-dose cytarabine induction followed by intermediate-dose cytarabine consolidation therapy. The patient presented with infection and rapidly increasing blood blasts. The diagnosis was consistent with AML-M7 with a normal karyotype. Peripheral blood blasts decreased rapidly upon low-dose cytarabine administration, and the patient achieved complete remission after two courses of low-dose cytarabine (10 mg/m² bid for 12 days). Consolidation therapy with intermediate-dose cytarabine (1.0 g/m² bid on day 1, 3 and 5) was then instituted without serious complication. He remained in complete remission at the time of writing 47 month after diagnosis. In spite of multiple poor prognostic factors, this patient showed excellent treatment outcome through low-dose cytarabine induction and intermediate-dose cytarabine consolidation. It needs to be validated whether acute leukemia with a megakaryocytic morphology is exceptionally sensitive to cytarabine. (Korean J Hematol 2009;44:244-248.)

Keywords: Acute myeloid leukemia, Acute megakaryocytic leukemia, Elderly, Low-dose cytosine arabinoside, Intermediate-dose cytosine arabinoside