Transient abnormal myelopoiesis in non‐ D own syndrome neonate

We encountered a case of neonatal acute megakaryoblastic leukemia not associated with D own syndrome ( DS ). Molecular cytogenetic analysis of leukemic blast cells indicated that increased blast cell status was caused by transient abnormal myelopoiesis with trisomy 21 and GATA 1 mutation. Based on these molecular cytogenetic data, intensive chemotherapy was avoided, and the patient was successfully cured with low‐dose cytarabine. Morphologically, leukemic blast cells of acute megakaryoblastic leukemia in a non‐ DS neonate are indistinguishable from a blast cell of transient abnormal myelopoiesis. The possibility of transient abnormal myelopoiesis should be carefully considered before intensive chemotherapy is adopted.