Crohn's disease is characterized by transmural inflammation, meaning the inflammation affects all layers of the gastrointestinal tract wall. This feature distinguishes it from ulcerative colitis, which involves only the mucosa and submucosa. The transmural nature in Crohn's can lead to complications such as fistulas, strictures, and bowel perforation. These deeper layers of involvement explain the segmental, "skip lesion" pattern seen in Crohn’s disease during surgical and pathological evaluation. Recognizing transmural inflammation is crucial for surgical decision-making and management of complications.

Reference: Robbins Basic Pathology, Kumar, Abbas, Aster, 10th Edition.