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.
2011 by The Japanese Society of Internal Medicine