Abstract
An 85-year-old female presented with watery diarrhea after taking the medication lansoprazole. Colonoscopic findings showed cat scratch colon (sharp longitudinal erosions) on the rectal colon. A colonic mucosal biopsy showed marked thickening of the subepithelial collagen bands, which were more than 10 μm thick. She was diagnosed as having collagenous colitis. After discontinuing the lansoprazole, the patient’s symptom improved. A case of collagenous colitis associated with cat scratch colon has rarely been reported in Japan and findings of cat scratch colon could be a useful endoscopic marker for collagenous colitis.
