Fistula-unexpected complication after rectal cancer surgery due to Zinner syndrome.

Zinner syndrome is an uncommon developmental defect of men's urogenital system, described as a triad of unilateral kidney underdevelopment, seminal vesicle cysts, and ejaculatory duct blockage. In our report, a patient had a diagnosis of Zinner syndrome only after treating recurrent rectal cancer. The patient presented with a postoperative perineal abscess and fistula. During the surgery, the abnormally extended ureter was damaged. The complications could be avoided if the presence of Zinner syndrome was confirmed before the surgery. The specific radiological signs of magnetic resonance and computed tomography must be considered. They could have predicted the patient's surgical outcomes.