[Malignant melanoma of male urethra: a case report]

A case of male urethral melanoma is reported. A 85-year-old male with a 2-month history of progressive, severe obstructive urinary symptoms and bloody urethral discharge was referred to us after an unsuccessful management at a local doctor. Physical examination revealed an ill looking old man with no evidence of nevi or other cutaneous pigmentation looking like malignant melanoma. Neither palpable periurethral mass nor inguinal lymphadenopathy was noted. RUG showed an irregular shadow defect in bulbous urethral regions. In cystourethroscopy, a raised nodular reddish black lesion in the urethra without adjacent satellite lesions was found. Histologic examination revealed that the tumor was made up of closely spaced, anaplastic, spheroidal or polyhedal cells. Intracellular brown pigment was richly present, gave a negative reaction for iron, but stained black with Masson-Fontana's method. Further examination for evaluating metastases including bone scintigraphy, computer tomographic scan, chest X-ray film were negative. Due to his poor risk, radical operation such as cystourethrectomy might be undesirable. We performed TUR to relieve urethral obstruction, because the patient refused cystostomy. He died of wide spread metastases at 6 months after the operation. This case seems to be the second report in the Japanese literature.