[Transitory abnormal myelopoiesis of the monoblastic form in a newborn infant with Down's syndrome and liver cirrhosis].

A case of 5-day old newborn infant with trisomy 21, who presented a leucocytosis (151 000/ml) with 60% of monoblasts and marked hepatosplenomegaly is reported. Transient abnormal myelopoiesis (TAM) was retained. TAM regressed spontaneously. However the baby died at the age of 50 days. The autopsy showed extramedullary hematopoiesis with marked monocytosis and liver cirrhosis of neonatal hepatitic origin. The pathogenesis of TAM in this case was discussed.