Merkel cell carcinoma: a report of gastrointestinal metastasis and review of the literature.

Merkel cell carcinoma (MCC) is an uncommon, highly aggressive cutaneous neoplasm of neuroendocrine differentiation with a poor prognosis. MCC most often presents as a painless, firm, raised lesion in sun-exposed sites of the head and neck region of the elderly. We report a case of a metastatic MCC to the stomach presenting as upper gastrointestinal bleeding. To our knowledge, this is the second reported case of MCC presenting as upper gastrointestinal bleeding and the first case confirmed by the newer immunohistochemical techniques. The literature is reviewed.