A 58-year-old man was admitted to our hospital with a seven-day history of right lower quadrant abdominal pain. Contrast-enhanced CT showed multiple diverticula and pericolic inflammation in the ascending colon. The patient was diagnosed as having colonic diverticulitis and treated with antibiotics. After hospitalization for 10 days, the patient improved and was discharged.
A month later, total colonoscopy was performed, which showed multiple colonic diverticula in the ascending colon and a polypoid lesion at the same site. The polypoid lesion was covered with normal colonic mucosa and the top of the lesion was reddish and slightly depressed. We obtained a biopsy specimen and noticed some fatty tissue at the site of the biopsy. We finally diagnosed the polypoid lesion as an inverted colonic diverticulum and immediately closed the biopsy site with endoclips. The patient was admitted and showed no complaints. He was discharged on day 4 of admission.
Inverted colonic diverticulum is a rare disease. It resembles a colonic polyp or submucosal tumor and may be misdiagnosed. Therefore, the possibility of this condition must be borne in mind when polypoid lesions are encountered, to avoid unnecessary biopsy or polypectomy, especially in patients with diverticular disease.
