Complicated giant diverticulum of rectosigmoid colon in elderly

Giant colonic diverticulum (GCD) is a rare condition defined by diverticular size over 4 cm. Its presentation is usually asymptomatic. We herein report a rare presentation of ruptured GCD in elderly man who suffered from abdominal pain. The patient underwent primary repair and ileostomy to shorten the operation time instead of Hartmann's operation. Post-operative CT revealed complicated GCD with rupture. The exact mechanism of GCD generation is questionable. Most of case is discovered by radiologic exam or computed tomography (CT) incidentally. The most common complications of GCD are perforation and abscess formation. Symptoms of GCD are like those of usual diverticulosis. But, considering the severity of complications, it is better to prioritize surgical treatment at diagnosis. •Giant colonic diverticulum (GCD) is a rare condition defined by diverticular size over 4 cm.•Most of patients are discovered by radiologic exam incidentally.•The most common complications of GCD are perforation following abscess formation with higher clinical significance.•Thus, it is better to prioritize surgical treatment at diagnosis.