Cat Scratch Colon | The Practicing Endoscopist

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'Cat scratch colon' refers to bright red, linear mucosal tears or lacerations that mimic cat scratches, typically seen in the right colon.
It is most commonly a benign, superficial result of barotrauma caused by entrapped CO2 or air during insufflation, particularly when there is a tight angulation in the distal ascending colon.
While usually an incidental and harmless finding requiring no treatment, its presence should prompt consideration of underlying conditions that predispose mucosa to barotrauma, such as collagenous or ischemic colitis.

A 75-year-old woman underwent colonoscopy for obscure gastrointestinal bleeding. Her procedure revealed a tortuous colon with numerous diverticula. Upon entering the ascending colon and cecum, multiple red mucosal lesions were found (Figure 1).

Figure 1. Endoscopic findings of "cat scratch colon." (A-C) Multiple bright red, linear marks on the mucosa of the ascending colon, resembling cat scratches. (D-F) A sharp, tight angulation in the distal ascending colon responsible for causing the barotrauma.

This was the characteristic appearance of “cat scratch colon.” Cat scratch colon is a colonoscopic finding characterized by mucosal tears or lacerations. These are usually a benign, superficial finding resulting from barotrauma during colonoscopy when CO₂ or air is used to insufflate the colon. Some underlying pathologies such as collagenous colitis or ischemic colitis may predispose to barotrauma and cat scratch colon. In this case, the etiology was pure barotrauma, resulting from CO₂ getting entrapped in the cecum and ascending colon due to a tight angulation in the distal ascending colon, which created a tight valve mechanism (Panels D, E, F).

In most cases, cat scratch colon is a harmless, incidental finding during colonoscopy and doesn't require specific treatment. However, it's important to recognize the finding and consider potential contributing factors.

Endoscopic view of linear red mucosal breaks (cat scratch colon) — Figure 1. Endoscopic findings of "cat scratch colon." (A-C) Multiple bright red, linear marks on the mucosa of the ascending colon, resembling cat scratches. (D-F) A sharp, tight angulation in the distal ascending colon responsible for causing the barotrauma.

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About the authors

Andrés Gutiérrez Moreira, MD

Gastroenterology Fellow, Universidad de la República (Uruguay); Visiting Fellow, Virginia Tech Carilion School of Medicine

Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay

Andrés Gutiérrez Moreira, MD, is a gastroenterology fellow at the Clínica de Gastroenterología "Prof. Carolina Olano" at Hospital de Clínicas, Universidad de la República in Montevideo, Uruguay, and was a visiting fellow at Virginia Tech Carilion School of Medicine in 2025. He earned his medical degree from the Universidad de la República in 2023 and is a member of the American Society for Gastrointestinal Endoscopy and the Sociedad Uruguaya de Endoscopía Digestiva.

Klaus Mönkemüller, MD, PhD, FASGE, FJGES, FESGE

Editor-in-Chief, The Practicing Endoscopist

Professor of Medicine, Carilion Memorial Hospital / Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA

Klaus Mönkemüller, MD, PhD, FASGE, FJGES, FESGE, is the editor-in-chief of The Practicing Endoscopist and the founder of EndoCollab. He is Professor of Medicine at Virginia Tech Carilion School of Medicine and a practicing endoscopist at Carilion Memorial Hospital in Roanoke, Virginia.

Dr. Mönkemüller has published extensively on endoscopic techniques and devices, with a particular focus on therapeutic endoscopy, foreign body removal, GI bleeding, and the use of caps and accessories in everyday practice. He lectures internationally and has contributed to multiple GI endoscopy textbooks and atlases.

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