Transient myeloproliferative syndrome/transient acute myeloid leukemia in a newborn with Down syndrome: a case report and literature review.

We report the case of a newborn with Down syndrome (DS) associated with transient acute myeloid leukemia (AML). The leukemic presentation resolved spontaneously without treatment just 4 weeks after birth. An abnormal hematopoietic function is a well-known characteristic of DS; however, acute leukemia is rare in newborns with this genetic disorder. The presence of peripheral blast cells matched generally by an equivalent quantity in the bone marrow may be considered a true leukemia that, although transient, may predict the development of a generally megakaryoblastic AML within the first few years of life. This leukemia is not transient and must be treated accordingly. The cytogenetic and molecular abnormalities involving DS chromosome 21 in leukemogenesis in these patients are not well understood. In DS, AML, transient or not, generally shows cytogenetic and molecular aspects that differ from those of adult acute leukemias.