Down syndrome with myelodysplasia of megakaryoblastic lineage.

The association between Down syndrome and acute myelogenous leukemia (AML) has been well documented. AML in Down syndrome is usually a specific type of megakaryoblastic leukemia (M7, AMKL). A myelodysplastic syndrome generally precedes this malignancy. Down syndrome patients with AMKL have a much better prognosis than other children with AML. A case study of a 22-month-old female with Down syndrome and myelodysplastic syndrome of a megakaryoblastic lineage is presented here. Upon admission to a pediatric hematology/oncology clinic, flow cytometry results reported a distinct population of phenotypically abnormal myeloblasts expressing myeloid antigens and the immature cell markers. The patient was placed on a national research group study and began chemotherapy treatment. To date she has received two courses of cytarabine (ara-c) and daunorubicin therapy, which were tolerated well, and is awaiting her third course. Her blood counts stabilize for a while after treatments and her prognosis is good.