TAM in Down Syndrome — RACP Paediatrics MCQ

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HardNeonatologyTAM in Down SyndromeRACP Paediatrics

A term neonate with trisomy 21 is found to have a leucocytosis of 80 x 10^9/L with circulating blasts on blood film at day 2 of life. He is otherwise asymptomatic. What is the most likely diagnosis?

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Correct answer: E — Transient abnormal myelopoiesis (transient myeloproliferative disorder)

Transient abnormal myelopoiesis (TAM) occurs in approximately 10% of neonates with trisomy 21. It presents with circulating blasts, often with leucocytosis, in the first weeks of life. Most cases resolve spontaneously within 1-3 months. However, approximately 20% of these infants subsequently develop acute megakaryoblastic leukaemia (AMKL) within 1-3 years, requiring close haematological follow-up.

Reference: RCH Melbourne – 2024 – Clinical Practice Guidelines: Haematological Conditions in Down Syndrome