A 51 yrs old women who underwent a screening colonoscopy. She has no significant gastrointestinal symptoms. Her past medical history was significant for Hypertension and she was treated with atenelol. She has a 1.2 cm pedunculated polyp in descending colon which was snared with standard setting. Histology of that polyp was 'mucus-containing cysts partially lined with colonic epithelium located in the submucosa is diagnostic of colitis cystica profunda'. In the colon the presence of histologically benign mucus-containing cysts partially lined with colonic epithelium located in the submucosa is diagnostic of colitis cystica profunda. Most instances of colitis cystica profunda are localized polypoid lesions located in the rectum. Diffuse or segmental colonic involvement may occur occasionally, usually in association with inflammatory bowel disease or diffuse colonic infections. Circumstantial evidence strongly suggests that colitis cystica profunda follows mucosal ulceration of varied etiologies and is probably due to submucosal entrapment of colonic glands following healing of ulceration. At the present time localized colitis cystica profunda is considered to be closely related to the solitary rectal ulcer syndrome, prolapsing mucosal folds in diverticular disease, and inflammatory cloacogenic polyp. All of these conditions are linked to mucosal prolapse and represent parts of the spectrum of what has recently been called the “mucosal prolapse syndrome.” Colitis cystica profunda has also been reported following radiation therapy and self-inflicted rectal trauma. There is also evidence that submucosal entrapment of colonic glandular tissue may be a complication of surgery due either to mechanical displacement of glandular tissue. In an early report six of nineteen patients with localized rectal colitis cystica profunda had previous rectal surgery.