This portion of terminal ileum demonstrates the gross findings with Crohn's disease. Though any portion of the gastrointestinal tract may be involved with Crohn's disease, the small intestine--and the terminal ileum in particular--is most likely to be involved. The middle portion of bowel seen here has a thickened wall and the mucosa has lost the regular folds. The serosal surface demonstrates reddish indurated adipose tissue that creeps over the surface. Serosal inflammation leads to adhesions. The areas of inflammation tend to be discontinuous throughout the bowel. The endoscopic appearance with colonoscopy, demonstrating mucosal erythema and erosion, is seen below