This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rectum, Subject name: Surgery
Paget's disease of anal canal is: 
Select and explain. 
A. Squamous cell carcinoma in situ, B. Squamous cell adenoma, C. Intra-epithelial adenocarcinoma, D. Marginal anal cell carcinoma
C: Intra-epithelial adenocarcinoma
Answer: C: Intra-epithelial adenocarcinoma 
Explanation: Ans. (c) Intra-epithelial adenocarcinoma Ref: Sabiston 19th Edition, Page 1405Paget's Disease of Anal Canal* It's the superficial manifest of an intraepithelial adenocarcinoma.* Most common site is breast* Most common site of extra mammary Paget's disease- Anogenital > Axilla* Most common site in females: Vulva* Paget's cells- Foamy and Vacoulated, PAS+ve , Mucicarmine and Alcian blue +, Cytokeratin 7 is also positive* Diagnosis made on biopsy* Wide local excision is treatment of choice.