Malignant vaginal melanoma with metastases to the papilla of Vater in a dialysis patient: a case report.

Malignant vaginal melanoma is an extremely rare clinical condition, with less than 150 cases reported to date. A dialysis patient had primary vaginal melanoma with metastases to the papilla of Vater. Gastroduodenoscopy revealed a polypoid tumor. Histological findings revealed vimentin, S-100 protein, HMB45, MelanA-positive sarcoma-like cells. This staining pattern indicated that this tumor was a malignant melanoma of the papilla. Analysis of an autopsy specimen of the papilla of Vater revealed metastasis from the primary vaginal melanoma. Metastasis of a malignant tumor to the gastrointestinal tract, especially to the papilla, is uncommon. Melanoma should be considered in the differential diagnosis of primary gastrointestinal tract malignancy.