This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intestinal Polyps, Colon & Anal Cancer, Subject name: Pathology
Histological finding of solitary rectal ulcer syndrome is: 
Select and explain. 
A. Thick collagen band under endothelial layer, B. Intraepithelial collection of lymphocytes, C. Crypt hypoplasia, D. Increased muscle layer proliferation
D: Increased muscle layer proliferation
Answer: D: Increased muscle layer proliferation 
Explanation: Mucosal prolapse syndrome/ solitary rectal ulcer syndrome d/t chronic mechanical stimulation Recognized in prolapsing colostomies, inflammatory polyps, solitary ulcer or prolapsing hemorrhoid at the site of rectum - Microscopically, there is Intercryptal erosion, hyperplasia of crypts (some have peculiar diamond shape). Obliteration of lamina propria by fibroblasts, elastin & smooth muscle cells from muscularis mucosae Reduction in number of lymphocytes & plasma cells Thickening of the muscularis mucosa with splaying of its fibers.