A 28 year old female with a several-year history of intermittent diarrhea and abdominal pain is seen for inflammatory bowel disease. Endoscopic evaluation of her terminal ileum, colon, and rectum is undeaken. Which of the following endoscopic observations is more indicative of Crohn's disease than of ulcerative colitis?

Crohn's disease is frequently associated with "skip lesions," discontinuous areas of active disease in the colon and small intestine with intervening segments that appear normal. This is in marked contrast to ulcerative colitis, which most commonly shows continuous mucosal involvement. Both ulcerative colitis and Crohn's disease can show mucosal atrophy. Chronic mucosal inflammation produces glandular atrophy, and a loss of mucosal folding. Mucosal ulceration is seen in both Crohn's disease and ulcerative colitis. The ulcers of Crohn's disease are generally described as linear fissures, following the longitudinal axis of the intestine. Ulcerative colitis typically produces broad, extensive areas of ulceration. Pseudopolyps are most commonly associated with ulcerative colitis, and represent the islands of spared mucosa between the broad ulcerations. Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 14. Gastrointestinal Pathology. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.