[Primary malignant melanomas of the urethra. Apropos of 4 cases].

The authors report four cases of primary malignant melanoma of the urethra. The rarity of these lesions can lead to their mis-diagnosis. Only histological examination of a biopsy specimen stained with Fontana stain can confirm the diagnosis. These tumours have a very poor prognosis because of their tendency to locally invade the corpus cavernosus in men and the vulva and vagina in women. These lesions carry a high risk of lymph node and metastatic dissemination. For very limited tumours, the authors recommend a relatively extensive urethrectomy (2/3 of the urethra in women and amputation of the penis in men with a perineal urethrostomy) completed by interstitial irradiation with irridium 192 (6,000 rads) and inguinal lymphadenectomy. In larger tumours, with lymph node invasion, the very brief survival time makes extensive excision inappropriate. Limited palliative surgery is to be preferred. Radiotherapy and chemotherapy have no proven effectiveness.