Presentation of Acute Megakaryoblastic Leukemia Associated with a GATA-1 Mutation Mimicking the Eruption of Transient Myeloproliferative Disorder.

Children with trisomy 21 are prone to developing hematologic disorders, including transient myeloproliferative disorder (TMD) and acute megakaryoblastic leukemia (AMKL). The papulovesicular eruption of TMD provides an important clue to the diagnosis. In contrast, AMKL rarely has associated cutaneous findings. We report the case of a 22-month-old child with trisomy 21 who presented with the acute onset of diffusely scattered and crusted papules, plaques, and vesicles. A thorough infectious evaluation was negative and the patient was unresponsive to empiric antibiotic and antiinflammatory therapies. Complete blood count (CBC) was notable for mild pancytopenia, with a normal peripheral smear. Two weeks later he was reassessed and found to have a population of blasts on repeat CBC. Subsequent evaluation ultimately led to a diagnosis of AMKL. This is the first reported case of a cutaneous eruption in a young child with Down syndrome and transformed AMKL. When children with trisomy 21 present with the acute onset of crusted papules and vesicles that cannot be accounted for by an infectious etiology, a diagnosis of AMKL should be considered even in the absence of a history of TMD.