Primary melanoma of the urethra: a rare neoplasm of the urinary tract.

Primary melanomas of the genitourinary tract are rare and constitute less than 1% of all melanomas. Since the clinical presentation of urethral melanoma is similar to commoner urothelial carcinomas, there is frequent delay in diagnosis. A 65-year-old female presented with bleeding per urethra for 1 month. Cysto-urethroscopy showed a gray-white polypoidal tumor in the distal urethra. A biopsy from the tumor showed sheets of cells with moderate cytoplasm, and central vesicular nucleus with prominent nucleolus. Immunohistochemistry for HMB-45 and S-100 protein was positive in the tumor cells. A diagnosis of urethral melanoma was made and radical cysto-urethrectomy with total hysterectomy was done. There was no residual tumor in the urethra; however, sections from bladder neck showed pagetoid spread of melanoma cells in urothelium. No melanocytic lesion was found elsewhere, and a diagnosis of primary melanoma of urethra was rendered. Urethral melanomas are rare tumors, having clinical presentation similar to much commoner urothelial neoplasms. Due to the poor prognosis, the clinician and the pathologists should keep this diagnosis in mind when dealing with urethral tumors with unusual morphology.