In which disease is the "cobblestone mucosa" a characteristic finding?

Cobblestone mucosa is a characteristic finding in Crohn's Disease, which is a type of inflammatory bowel disease (IBD). This appearance is due to the presence of deep ulcers and fissures interspersed with areas of normal mucosa, leading to a patchy and irregular surface that resembles a cobblestone pathway when viewed during an endoscopic examination. The transmural inflammation in Crohn's affects not just the inner lining of the gastrointestinal tract but also deeper layers, contributing to its unique lesions and the typical cobblestone appearance.

This finding is not seen in ulcerative colitis, which generally presents with continuous lesions starting from the rectum, and is characterized by a more smooth and ulcerated mucosa rather than the irregular, cobbled appearance. Diverticulitis typically involves diverticula in the colon and presents with inflammation that does not produce the cobblestone pattern seen in Crohn's Disease. Gastritis, which is inflammation of the stomach lining, similarly does not exhibit cobblestone mucosa as it has a different pathophysiological presentation. Thus, the presence of cobblestone mucosa is specifically indicative of Crohn's Disease among the options listed.