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': 'True about Biliary cystic adenocarcinoma \nSelect and explain. \nA. CT scan is used for diagnosis, B. CA 19-9 is elevated, C. intrahepatic location, D. Extrahepatic location', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hepatic cystadenocarcinoma arising from pre-existing cystadenoma with mesenchymal stroma, which occurs only in young females,\xa0carries good prognosis resection is the treatment\xa0it carries a good prognosis. MRI is diagnostic. \nUS/CT scan is also helpful. ERCP is done to identify communication with\xa0the biliary\xa0system usually to proximal left hepatic duct.', 'role': 'assistant'}]