[Primary melanoma of the bladder. A case report].

Primary melanoma of the urinary bladder is rare. We report a case of a 58-year-old woman, who presented with a 4 month history of dysuria and hematuria. A biopsy indicated a diagnosis of invasive melanoma and a partial cystectomy was performed. The neoplasm had invaded the entire thickness of the bladder wall and the neoplastic cells were positive for Melan A and HMB-45. Four months later a urinary bladder measuring 13×7×5cm was sent for histopathology. Melanoma, melanosis and a melanocytic nevus were seen; the latter was confirmed by the positivity to melanocytic markers of non-atypical cells in both the urothelial basal layer and areas distant from the tumour. The patient died nine months later.