ABSTRACT
The latest WHO (2017) classification describes the hematological abnormalities of Down's syndrome as a separate entity under 'Myeloid proliferations associated with Down's syndrome'. It includes Transient Abnormal Myelopoiesis and Myeloid leukemia of Down's syndrome. Here we report a case of a 3 days old neonate with Down's syndrome, presenting with a leukemic blood picture. The baby had icterus, fever and hepatosplenomagaly. Peripheral blood showed megakaryoblasts and giant platelets. A diagnosis of transient abnormal myelopoiesis was made by confirming with karyotyping and immunophenotyping. We attempt to address all the diagnostic challenges faced by a clinician and pathologist same, upon encountering such a case,by following an algorithmic approach. The mandatory need for follow up and cytogenetic studies in identifying high risk cases that will become myeloid leukemia of Down's syndrome are stressed. Our case also throws light upon the significance of identification of GATA1 mutation in diagnosing and prognostication of such cases.