Malignant melanoma of the bladder: A case report.

Primary malignant melanoma of the bladder is very rare. Rather than being a primary lesion, malignant melanomas of the bladder are more commonly metastatic lesions. The histopathological appearance largely does not differ from that of melanoma at other body sites. It is often difficult to discriminate whether a bladder melanoma is primary or metastatic. Therefore, a careful review of histological features and performing necessary immunohistochemical staining procedures for S-100 protein and HMB-45 are very important in achieving a correct diagnosis. We report a case of hypomelanotic malignant melanoma of the bladder. Despite the variety of therapies available for primary melanomas of the bladder, the prognosis is still poor.