A neonate with a vesiculopustular rash.

Transient myeloproliferative disorder (TMD) is a unique form of acute megakaryocytic leukemia (AMKL) that spontaneously regresses and is found in 3% to 10% of neonates with Down syndrome (DS). We report the case of a neonate with DS who presented with a widespread vesiculopustular eruption as an initial sign of TMD. Complete blood count was normal but peripheral smear revealed circulating megakaryoblasts. The severity of skin lesions correlated with the blast count. By age 2 months the TMD resolved and the patient remains disease-free after 18 months of follow-up. Several important features of TMD are highlighted: skin findings may provide an important clinical clue to TMD diagnosis; manual review of the peripheral smear is necessary when TMD is suspected; and patients with a history of TMD have a very high (∼30%) risk of recurrence with a persistent AMKL within the first 3 years of life. Copyright 2015, SLACK Incorporated.