This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Plastic Surgery and Skin Lesions, Subject name: Surgery
[{'content': 'Lipoma becomes malignant commonly at which site: \nSelect and explain. \nA. Subcutaneous, B. Sub-aponeurotic, C. Retroperitoneal, D. Intermuscular', 'role': 'user'}, {'content': 'Answer: C \nExplanation: RETROPERITONEAL LIPOMA These swellings sometimes reach an immense size Retroperitoneal lipoma is often malignant (liposarcoma) and may increase rapidly in size A retroperitoneal lipoma sometimes undergoes myxomatous degeneration Clinical Features Swelling or indefinite abdominal pain More common in women Diagnosis Diagnosis is usually by ultrasound and CT scanning.', 'role': 'assistant'}]