<prompt> Skip granulomatous lesions are seen in ?Ulcerative colitisCrohns diseaseWhipples diseaseReiters disease  <response>: Ans. is b i.e., Crohns Disease Features of CD In the affected segment, mesentric fat wraps around the bowel surface -- creeping fat o The intestinal wall is rubbery and thick, as a consequence of edema, inflammation, fibrosis, and hyperophy of the muscularis propria -- lumen is almost always narrowed -- string sign on barium meal. o A classic feature of CD is the sharp demarcation of diseased bowel segments from adjucent uninvolved bowel. o When multiple bowel segments are involved, the intervening bowel is normal -- skip lesions. o There are serpentine linear ulcer along the axis of bowel. As the intervening mucosa tends to be relatively spared, the mucosa acquires a coarsely textured Cobblestone appearance. o Narrow fissures develop between the folds of the mucosa. Fissures can penetrate deeply through the bowel wall and leading to bowel adhesions and serositis. o Fuher extension of fissures leads to fistula or sinus tract formation. o There is transmural inflammation affecting all layers of bowel wall. Sarcoid like noncaseating granulomas may be present in all tissue layers. o Neutrophilic infiltration into the crypts results in formation of crypt abscess. o Fibrosis of the submucosa, muscularis propria, and mucosa eventually leads to stricture formation. There is an increased incidence of cancer of GIT in patients with long-standing CD, but the risk of cancer in CD is considerably less than in patients with chronic UC. 