Computed tomographic appearance of urachal carcinoma associated with urachal diverticulum misdiagnosed by cystoscopy.

Urachal carcinoma associated with the urachal diverticulum is rare. We present a surgical case of this condition that was initially diagnosed as bladder urothelial carcinoma by cystoscopy, but was then correctly diagnosed by computed tomography (CT). Whereas the CT appearance mimicked that of bladder cancer, accurate localization of the lesion and identification of the median umbilical ligament clarified diagnosis.