Transient myeloproliferative disorder and acute myeloid leukemia: study of six neonatal cases with long-term follow-up

Six neonates with hematological and clinical pictures indistinguishable from acute myeloid leukemia were studied. Two patients had Down syndrome and three others had either +21 or i(21q) chromosomal abnormalities in their blood cells at presentation. Granulocyte-macrophage colony-forming unit assays performed in bone marrow and peripheral blood mononuclear cells revealed abnormal growth patterns in two patients; both died of progressive disease of acute myeloid leukemia. All the other four neonates with normal in vitro cell growth pattern had spontaneous remission within 7 months. Of these four patients, one remains well and in remission for 8 years and the other three developed acute myeloid leukemia at the ages of 15, 32 and 19 months, respectively. We conclude that the in vitro cell growth pattern is helpful to distinguish transient myeloproliferative disorder from congenital acute myeloid leukemia and that patients with the former condition are at risk to develop acute myeloid leukemia subsequently.