Earliest change seen in Crohn's disease:

Ans. (a) Aphthous ulcersRef: Surgery Sixer 2nd edition, Page 420Pathologic features:Crohn's diseaseUlcerative colitis* Transmural inflammation* Noncaseating granulomas* Aphthous ulcers are the earliest manifestation* Serpiginous/Bear claw linear ulcers* Cobblestone appearance* Skip lesions* Fistulas* As the disease progresses, the mucosa begin to erode leaving only small islands of mucosa that resemble polyps but are actually pseudo polyps* Crypt abscesses* Confined to the mucosa and submucosa, in the most severe forms of the disease, such as fulminant colitis or toxic megacolon, the disease process may extend to the deeper muscular layers of the colon and even to the serosa(Crypt abscess and pseudopolyps can also occur in Crohn's disease but less common than ulcerative colitis )