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
[{'content': 'Five days self-limiting anal pain is due to: \nSelect and explain. \nA. Fissure, B. External thrombosed hemorrhoid, C. Fistula, D. Internal hemorrhoid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) External thrombosed hemorrhoidRef: Bailey and Love 27th Edition, Page 1360* Thrombosed external hemorrhoids is known as perineal hematoma* Sudden onset of Olive-shaped painful blue subcutaneous swelling at anal margin* If patient comes to you in 48 hours you can evacuate the hematoma or clot under local anesthesia* Untreated cases usually resolves in 5 days by forming fibrosis in majority.', 'role': 'assistant'}]