Transient Myeloproliferative Disorder related with Trisomy 21: Case Report

Abstract

Newborns with Down syndrome exhibit heightened leukemia risk, with up to 30% developing transient myeloproliferative disorder, a megakaryoblastic proliferation exclusive of this condition that typically resolves spontaneously within the first few months of life. We present the case of a male newborn with prenatal diagnosis of trisomy 21 born at 36+3 weeks of gestation via emergency cesarean section due to non-reassuring fetal status. Admited to the Neonatal Intensive Care Unit due to transient tachypnea of the newborn, requiring supplemental oxygen. Initial evaluation revealed severe leukocytosis (52,000/µL), thrombocytopenia (60,000/µL), and 43.5% of blasts on the peripheral blood smear, suggestive of transient myeloproliferative disorder, posteriorly confirmed in immunophenotyping. Conservative treatment was initiated, incluiding hyperhydration, platelet transfusion, diuretics for pericardial effusion, and antibiotics for nosocomial sepsis. Peak leukocytosis improved progressively, normalizing by day 11, with no need for chemotherapy. The red blood cell count remained normal throughout hospitalization. He was discharged home at one month of age, mantaining regular clinical and haematological follow-up. The current case highlights diagnostic challenges that may lead to underdiagnosis of this haematological condition and the difficulty to establish disease-related complications. Also, emphasizes immunophenotyping’s diagnostic utility in avoind invasvie procedures, and demonstrates successful expectant management. However, the risk of disease progresssion to acute myeloid leukaemia is significant, underscoring the need for regular long-term follow-up in order to determine sustained remission.