[Cancer of the urachus. A rare form of tumors of the bladder].

Cancers of the urachus are very infrequent, making up 0.1% to 0.7% of all bladder tumors. This type of tumor affects male subjects in 60% to 75% of cases, in the 5th or 6th decade of live. In more than 90% of all cases, the lesion is a mucosecretory adenocarcinoma developing from embryonic remains within the wall of the bladder and respecting the superficial urothelium of the bladder, which is affected only secondarily, contrary to what occurs in the other adenocarcinomas of the bladder. The pathogenesis remains controversial, especially in the role of urachus patency and of bladder carcinogens. The diagnosis is most often established late, because of a long clinical latency. It is mainly based on ultrasonography and CT scan. Explorations of the bladder are useful only at an advanced stage. The prognosis is very poor, survival at 5 years ranging from 6.5% to 25% according to the authors. The treatment is mainly surgical. Only extensive resection with partial cystectomy extending to the peri- and supravesical environment, including the peritoneum and the umbilicus, and associated with pelvic lymphadenectomy may give some hope. Chemotherapy and radiation therapy, either alone or adjuvant, are disappointing. The prognosis may be improved only by an early diagnosis.