Transient neonatal myeloproliferative syndrome. Report of two cases

Transient neonatal myeloproliferative disorder (TMD) is an hematological condition characterized by an abnormal clonal proliferation of myeloid blasts in peripheral blood. 10% of Down ' s syndrome newborns develop this blood alteration. Myeloproliferative disorder remits within the first six moths of life in 80% of the patients. Most of reported cases have only required supportive therapy. However in 17% of this individuals the first clinical manifestations are life threatening disorders such as hepatic failure, or hemodynamic and respiratory disfunction, in these circumstances chemotherapy is indicated. TMD cannot be considered a benign disease since these patients are at a great risk to develop acute megacaryoblastic leukemia within the first 5 years of life. We present two patients with TMD who had a favourable course; both normalized the number of blast cells in peripheral blood while being monitored in a neonatal intensive care unit. Chemotherapy was not required. Management was limited to supportive measures are being followed as external patients.