Transient myeloproliferative disorder causing a vesiculopustular eruption in a phenotypically normal neonate

We report an unusual congenital vesiculopustular eruption arising in a neonate as the result of the transient myeloproliferative disorder (TMD) associated with trisomy 21. In this instance, the neonate was phenotypically normal, making the diagnosis more elusive. Initially the lesions were clinically suspicious for herpetic infection. The clinical scenario quickly became highly suggestive of leukemia cutis, given the infant's extremely high white blood cell count. Further examination revealed trisomy 21 in the leukemic cells and disomy 21 in the buccal keratinocytes, and a diagnosis of self-resolving TMD was made. Biopsy specimens of the lesions showed a sparse, perivascular, atypical, mononuclear infiltrate. We suggest that examination for a TMD be undertaken in neonates with a vesiculopustular eruption and leukemic white blood cell counts.