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': 'A 50 year old patient presents with a lesion in the midline involving the sacrum. It is found to be sclerotic. What is the most probable diagnosis ? \nSelect and explain. \nA. Metastatic, B. Chordoma, C. Osteosarcoma, D. Chondrosarcoma', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Chordoma Sclerotic lesion involving midline in the sacrum is likely to be chordoma. o It occurs most commonly at either end of notochord (midline) in following locations a) Sacrococcygeal region b) Clivus c) Suprasellar region", 'role': 'assistant'}]