Which of the following is the earliest change in intestine which occurs in Crohn’s disease?
Cobblestone appearance
Aphthous ulcer
Perforation
Stricture
Ref. Robbins Pathology. 9th edition. Page. 800
 
Crohns Disease

Present with skip lesions
Earliest lesion – Aphthous ulcers
Can involve whole of GIT – Form oral cavity to amus
Smoking is a risk factor
Fissure, fistula seen
Stricture seen
Gross features – Creeping pad of fat, Cobblestone appearance
Microscopy - Non caseating granuloma under microscopy, Transmural inflammation