Multifocal Merkel's cell tumors associated with a cutaneous dysplasia syndrome.

Multifocal Merkel's cell tumors developed in a 24-year-old patient with an unusual cutaneous dysplasia syndrome. The neoplasms behaved in an aggressive fashion, with the development of multiple lymph node metastases. In this case, the dermatologic syndrome had features of both dyshidrotic ectodermal dysplasia and the basal cell nevus syndrome. In addition to Merkel's cell tumors, basal cell carcinomas and actinic elastosis were seen in sun-exposed skin sites. These findings, in conjunction with a known tendency for Merkel's cell tumors to arise in solar-damaged areas, suggest a pathogenetic relationship between these neoplasms and the underlying cutaneous syndrome in this patient.