[Urachal diseases].

Urachal diseases are infrequent. Congenital affections include cysts, fistula, diverticulum, external sinus, and alternating drainage sinus. Ultrasonography and fistulography are useful for the diagnosis. Treatment of malformations is rarely conservative; it consists in urachal resection. Urachal tumours are frequently malignant and adenocarcinomas are the main histological form. CT scanning is useful for staging. Treatment of urachal carcinomas consists in urachal, umbilicus and bladder removal. Prognosis is poor.