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
[{'content': "Which of the following would be the best morphological feature to distinguish ulcerative colitis from Crohn's disease - \nSelect and explain. \nA. Diffuse distributions of pseudopolyps, B. Mucosal edema, C. Crypt abscesses, D. Lymphoid aggregates in the mucosa", 'role': 'user'}, {'content': "Answer: A \nExplanation: Pseudopolyps (inflammatory polyps) can be seen in both Crohn's disease and ulcerative colitis\nIn ulcerative colitis, the distribution of these pseudopolyps can be diffuse but in Crohn's disease, the distribution cannot be diffuse because a classic feature of crohn's disease is the sharp demarcation of diseased bowel segments from the adjacent uninvolved bowel. When multiple bowel segments are involved the intervening bowel is essentially normal (skip lesions).\n\nMucosal edema\n- The hallmark of both ulcerative colitis and crohn's disease is mucosal inflammation and chronic mucosal damage. So mucosal edema is a feature of both of these diseases.\n- The important point is that while in Ulcerative colitis these processes are limited to mucosa or submucosal, in crohn's disease these processes extend beyond the mucosa and submucosa and involves the entire wall.\n\nCrypt abscesses -\n\n- Crypt abscesses are produced due to infiltration of the neutrophil into crypt lumen.\n- These crypt abscesses are not specific for ulcerative colitis and may be observed in crohn's disease or any active\xa0inflammatory colitis.\n\nLymphoid aggregates in mucosa\n\nThe characteristic mucosal feature of idiopathic inflammatory bowel disease on histology includes —\ni.\xa0Distortion of crypt architecture\nii.Destruction and loss of crypt\niii.A marked increase in lymphocytes and plasma cells in lamina propria.\niv. These features are specific to inflammatory bowel disease and help to differentiate idiopathic inflammatory bowel disease from acute infectious colitis and other chronic colitis.", 'role': 'assistant'}]