[Primary neuroendocrine Merkel cell carcinoma of the skin]

A 78-year-old woman noticed a nodule on the dorsal aspect of the left lower leg which caused no symptoms but gradually increased in size. The raised, brown-red nodule, about 1.5 cm in diameter, was widely excised because malignancy was suspected. Light and electronmicroscopy revealed changes typical of Merkel-cell carcinoma. Immunohistochemistry demonstrated neuron-specific enolase and cytokeratin. No metastases were found. Together with Langerhans cells and melanocytes, Merkel cells belong to the three non-keratinocyte cell types of the epidermis.