[Transient abnormal myelopoiesis followed by acute leukemia in children with Down syndrome]

This report describes three cases with Down's syndrome. These cases initially had transient abnormal myelopoiesis (TAM), from which they recovered spontaneously. They finally developed into overt acute leukemia characterized by an increase of blasts, hepatosplenomegaly, and elevated lactic dehydrogenase. Of these three cases, one was thought to have ANLL, which broke out 5 months after spontaneous remission. The other two had ALL, each occurring 8 and 9 years later. Chromosomal abnormality, in addition to trisomy 21, was detected in blast cells from one of the patients with acute leukemia. All three patients with acute leukemia experienced complete remission. However, two of the three patients relapsed and died. It is noted in the literature that remission is permanent in most cases of TAM, and is rarely terminated by leukemic relapse. In view of our observations, the importance of following up on such patients who evidence apparent remission of their leukemia-like disorder is emphasized.