Which colonoscopy/endoscopy finding is most characteristic of Crohn's disease?

• A. Pseudopolyps without skip lesions.
• B. Patchy transmural inflammation with skip lesions.
• C. No inflammation despite active disease.
• D. Continuous mucosal inflammation starting in the rectum.

Answer: (B)

Crohn's disease is most characteristically seen on endoscopy as patchy, transmural inflammation with skip lesions. Transmural means the inflammation extends through all layers of the bowel wall, which helps explain complications like fistulas and strictures. The patchy distribution, with inflamed segments interspersed with normal-appearing areas, is a key distinguishing feature from ulcerative colitis. In ulcerative colitis you’d expect continuous mucosal inflammation starting at the rectum, and pseudopolyps are a UC-associated finding. So the description of patchy transmural inflammation with skip lesions best fits Crohn's disease.