A case of neonatal acute megakaryoblastic leukemia that was difficult to differentiate from transient abnormal myelopoiesis

Abstract

Acute megakaryoblastic leukemia (AMKL) often develops in neonates, and the prognosis differs depending on the gene mutation. A 0-day-old female with thrombocytopenia was transferred to our hospital. Physical examinations revealed severe hepatosplenomegaly, but no other external malformations. A blood test showed disseminated intravascular coagulation. We suspected that this was caused by an infection and thus we initiated antibiotic therapy and symptomatic treatment. The percentage of blast cells in peripheral blood increased from 2.7% to 11% by day 5. Therefore, bone marrow aspiration was performed. Flow cytometry indicated that the patient had transient abnormal myelopoiesis (TAM) or AMKL. The percentage of blast cells decreased to 2% without specific treatment. We therefore speculated that the patient had TAM without Down syndrome. However, we detected t(1;22)(p13;q13) by chromosome analysis of peripheral blood and therefore diagnosed the patient as having AMKL. Diagnosis of AMKL was complicated by the decrease in the percentage of blast cells, which occurs in TAM. We hope that polymerase chain reaction analysis will become readily available to facilitate the identification of gene mutations and thus differentiate between AMKL and TAM.