Merkel cell carcinoma: a report of three cases with neurone‐specific enolase activity

Abstract

Three cases are described of a primary cutaneous neoplasm occurring in elderly patients, histological and immunohistochemical features of which support an origin from Merkel cells. Microscopically sheets of uniform small cells filled the dermis, often with a prominent trabecular pattern. Ultrastructurally the cells showed neurosecretory granules, tangles of microfilaments, scattered mitchondria and occasional intranuclear rodlets. Immunohistochemical staining for neuronespecific enolase was positive and for prekeratin was negative in each case. The definitive diagnosis of Merkel cell tumour can be made with a combination of electron microscopy and immunohistochemistry.