Inverted Colonic Diverticulum: An Infrequent and Dangerous Endoscopic Finding

Inverted Colonic Diverticulum: An Infrequent and Dangerous Endoscopic Finding R. Merino, T. Kinney, R. Santander, R. Yazigi, C. Navarrete, M. Saenz, R. Saenz Background: Inverted Colonic Diverticula (ICD) can be misinterpreted as elevated polypoid lesions, and biopsy or endoscopic resection of these lesions can lead to severe complications. These important lesions are rarely reported in the medical literature and marginally mentioned in classic texts. The aim of this study is to describe the endoscopic characteristics of ICD to avoid misdiagnosis and to report the frequency of these lesions in a large endoscopic series. Materials and Methods: A retrospective analysis was performed of all patients undergoing colonoscopy at our institution between July 2001 and July 2004 using Medicaps 2.0 InfoCYS endoscopic database and selecting patients diagnosed with ICD. Patient characteristics as well as lesion characteristics were recorded, including location, endoscopic characteristics, and the presence of synchronous polypoid lesions.The following endoscopic characteristics were considered in diagnosing ICD: 1) elevated sessile appearance with fine concentric folds surrounding the lesion, 2) mucosal pattern on lesion is similar to surrounding mucosa, 3) umbilicated appearance, 4) found in an area of diverticula, 5) surrounding fine concentric folds enhance with Methylene Blue, and 6) lesion reverts to typical diverticular appearance with direct water infusion, air insufflation, or gentle pressure with biopsy forceps. Results: Among 4508 colonoscopies performed in the selected period, 33 (0.7%) were diagnosed with ICD according to the endoscopic criteria above. Mean patient age was 62.3 years, with 7/9 male/female ratio. 89% of ICD were in an area of multiple colonic diverticula, and 75% were located in the sigmoid colon. One had active bleeding from the inverted diverticulum and was treated with injection therapy. 2 cases required gentle pressure with the biopsy forceps for diagnosis and the remaining were diagnosed according to the other referred endoscopic criteria. No biopsies or resections were performed. There were no complications in this series. Conclusion: ICD is a rare endoscopic finding (0.7%) that is occasionally complicated by local bleeding. Misdiagnosis could be dangerous as these lesions appear similar to sessile polyps, and biopsy or endoscopic resection could lead to serious complications. The endoscopic criteria described should be considered to avoid complications.