[Primary neuroendocrine carcinoma of the skin (Merkel cell tumor)].

Three cases of neuroendocrine carcinoma of the skin studied by light and electron microscopy and by immunohistochemical methods, are presented. It is generally accepted that these tumors originate from Merkel's cells. Some consider that they belong to the group of APUD-omas. Positive findings of epithelial (EMA, CAM 5.2) and neuroedocrine marker (NSE) in these three cases support the hypothesis of neuroendocrine differentiation in a neoplasm of epithelial origin.