This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
All of the following are true regarding Crohn disease except: March 2008 
Select and explain. 
A. Skip lesions, B. Inflammation limited to mucosa, C. Recurrence common after surgery, D. Fistulae formation is seen
B: Inflammation limited to mucosa
Answer: B: Inflammation limited to mucosa 
Explanation: Ans. B: Inflammation limited to mucosaFeatures of Crohn disease:Bowel region: Ileum, colonDistribution: skip lesionStricture formation: YesWall appearance: thickInflammation: transmuralUlcers:deep, knife-likeLymphoid reaction: markedFibrosis: markedSerositis: markedGranuloma formation: Yes (35%)Fistula/sinuses: YesFat/vitamin malabsorption: YesRecurrence after surgery: CommonToxic megacolon: No