Which of the following is the earliest change in intestine which occurs in Crohn’s disease?: (A) Cobblestone appearance, (B) Aphthous ulcer, (C) Perforation, (D) Stricture
Answer is B. 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