Colitis Cystica Profunda

Abstract

Colitis cystica profunda is a benign condition which may mimic carcinoma of the colon from both a radiologic and a pathologic standpoint. The lesion is characterized by intramural mucus-containing cysts, usually localized to the rectosigmoid region. The patients are young adults who often present with complaints of rectal bleeding and/or mucus in the stool. Microscopically, the cysts lie deep in the muscularis mucosae, differing from the superficial lesions of colitis cystica superficialis seen in patients with sprue and pellagra. Normal colonic epithelium lines the cysts, and the intraluminal mucin stains basophilic with hematoxylin and eosin. Evidence of chronic inflammation often accompanies the cysts. Grossly, the bowel wall appears thickened, and nodular polypoid foci are sometimes seen on proctoscopic examination. Small ulcerations may be present on the overlying mucosa. The roentgen picture is one of an intraluminal nodular space-occupying lesion or lesions. Out-pouchings of barium may be present, suggesting ulceration. The first report in the American medical literature by Epstein et al. (1) described four cases of this condition. They postulated that “the lesion probably results from herniation of colonic mucosa through a muscularis mucosae which is congenitally weak or damaged by an inflammatory disease; or perhaps is the result of re-epithelization of deep undermining ulcers.” Brynjolfsson and Haley (2) also attempted to elucidate the pathogenesis of this lesion by experimental work in rats. Additional cases have been reported from the Massachusetts General Hospital (3) and from the Armed Forces Institute of Pathology (4). Allen (5) reported three cases of “hamartomatous inverted polyps of the rectum,” all showing the features described in colitis cystica profunda. We recently encountered a case of this condition which illustrates well the roentgen characteristics of a nodular polypoid mass in the rectum on barium enema examination (Fig. 1). We feel that a report of this condition in the radiologic literature is indicated to ensure that radiologists are aware of the lesion and to stress the need to differentiate it from more ominous conditions in the rectosigmoid area. This 23-year-old Caucasian female registered nurse visited her physician with a complaint of spotty rectal bleeding that was not associated with any other signs or symptoms. She had been in good health, but her anxiety was now heightened because only three months earlier an adenocarcinoma of the rectum had been discovered in her mother. Sigmoidoscopy revealed a thickened mucosal area, measuring 1.5 × 1.5 cm in diameter, on the anterior wall of the rectum at the level of the cervix uteri. The mucosa appeared intact, but suggestive of possible underlying inflammation. The lesion was biopsied through the sigmoidoscope. Microscopic sections (Fig. 2) showed continuation of the colonic mucosa into a mucin-producing cyst within the muscularis mucosae.