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

Primary neuroendocrine carcinoma of the skin (Merkel cell tumor), a rare malignancy originating from the skin, has only been established in the recent years. It has a main predilection on the skin in the head and neck region with an obvious tendency of local recurrence and early metastasis. Histopathologically, it resembles the neuroendocrine carcinoma from other sites of the body in morphology, immunohistochemistry and ultrastructure. Diagnosis of this tumor is quite difficult. Based upon two of our cases as verified by electron microscopy and/or immunohistochemistry, the clinical and pathological features of this tumor are described and the literature reviewed.