Combined squamous cell carcinoma and Merkel cell carcinoma of the vulva: Role of human papillomavirus and Merkel cell polyomavirus.

HPV: human papillomavirus MCC: Merkel cell carcinoma MCV: Merkel cell polyomavirus PCR: polymerase chain reaction SCC: squamous cell carcinoma M erkel cell carcinoma (MCC), an uncommon and highly aggressive cutaneous malignancy, usually occurs on the sundamaged skin of the elderly and is characterized by coexpression of neuroendocrine markers and CK20, a discriminant from other types of visceral neuroendocrine neoplasias. Since the discovery of Merkel cell polyomavirus (MCV), many researchers have confirmed its presence in about 80% of cutaneous MCCs. Although some cutaneous MCCs were reported to be associated with squamous cell carcinomas (SCCs), such combined cases accounted for only aminor portion and the viral status appeared to be different from pure MCC. Rarely, primary MCCs occur on the female vulva, with or without combined SCCs, the latter is often human papillomavirus (HPV) related.