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: Surgery
[{'content': 'Abdominal ultrasound of a patient showed gall bladder with diffuse wall thickening and hyperechoic nodules at the neck and few comet tail aifacts. What is the most likely diagnosis? \nSelect and explain. \nA. Adenomyomatosis, B. Adenocarcinoma of gall bladder, C. Xanthogranulomatous cholecystitis, D. Chelesterol crystals', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Adenomyomatosis is a benign condition characterized by hyperplastic changes of unknown etiology involving the gallbladder wall. It causes overgrowth of the mucosa, thickening of the muscular wall, and formation of intramural diveicula or sinus tracts termed as Rokitansky-Aschoff sinuses. Ultrasound shows a thickened gall bladder wall, punctate hyperechoic reflectors with comet tail aifacts.', 'role': 'assistant'}]