Which finding on imaging or endoscopy is most supportive of Crohn's disease?

• A. Patchy transmural inflammation with skip lesions and terminal ileum involvement.
• B. Continuous mucosal inflammation starting from the rectum.
• C. Mucosal pseudopolyps without skip lesions.
• D. No inflammation on imaging.

Answer: (A)

Crohn disease shows patchy, transmural inflammation that can affect any part of the GI tract, most often the terminal ileum, with segments of diseased tissue separated by normal bowel—skip lesions. This full-thickness involvement and discontinuous distribution explain why this pattern on imaging or endoscopy is most supportive of Crohn's, and it also accounts for complications like fistulas and strictures.

In contrast, continuous mucosal inflammation starting from the rectum points to ulcerative colitis, mucosal pseudopolyps without skip lesions also fit UC features, and no inflammation on imaging would not align with active Crohn's.