Metastasis to the penis from malignant melanoma: case report and review of the literature.

A case of metastatic malignant melanoma to the shaft of the penis is described and the literature reviewed to collate the incidence of primary sites which metastasize to the penis. Less than 260 cases of metastasis to the penis have been reported. Of these, 76% are from genitourinary primary sites and 17% are from gastrointestinal primary sites but only one case of metastatic melanoma to the penis has been previously reported. The described case presented with painful priapism while receiving combination chemotherapy for metastatic disease. A CT scan demonstrated a deposit in the left corpora cavernosa and needle aspiration cytology of a plaque attached to the shaft confirmed malignant melanoma cells. Palliation of the painful priapism was achieved by treatment with radiotherapy using large doses per fraction. Retrograde venous or lymphatic spread may have been the cause of a metastasis at this site. Prognosis is very poor.