The urachus is a structure between the top of the bladder and the umbilicus (the belly-button). In the fetus the vessels of the umbilical cord pass through the urachus. At birth when the umbilical cord is clamped the components of the urachus no longer function and they typically collapse. In rare instances part or all of the urachus may remain patent (open). The cells that line the wall of a patent urachus have a permanent risk of transformation into cancer, specifically adenocarcinoma. Urachal cysts can be found incidentally on radiologic imaging done for other reasons, or as a result of symptoms that develop if they communicate with either the bladder or umbilicus. Urachal cysts can be a cause of recurrent urinary tract infection or mucus drainage into the urine or umbilicus. They may also cause hematuria (blood in the urine). Urachal cysts and primary tumors of the urachus can grow large and press upon surrounding structures. All urachal cysts and tumors require surgical removal. This is often accomplished through a robotic approach. See Other Robotic Procedures and Robotic Cystectomy for more information.