This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2018, Subject name: Orthopaedics
[{'content': "A patient has history of A 2 years back; at the same sight he developed pain and swelling. X - ray shows the following features. What will be the diagnosis? \nSelect and explain. \nA. Osteogenic sarcoma, B. Ewing's sarcoma, C. Chronic osteomyelitis, D. Multiple myeloma", 'role': 'user'}, {'content': 'Answer: C \nExplanation: * X-ray shows a deformed bone with holes/cavities in the bone.* Chronic Osteomyelitis: Its characteristic feature is sequestrum (dead bone in a cavity) with involucrum (live bone) around it. There is discharge of pus draining through cloacae and track sinuses in the cavity.* Osteosarcoma: aggressive tumor, there will be no history of trauma and there will be presence of growth coming out. There may be Codman\'s triangle and "sunburst" appearance in x-rays.* Ewing\'s sarcoma: found in diaphysis and will be in younger people. History of trauma is not significant. Radiographically, periosteal reaction of "onion-skin appearance" is present.* Multiple myeloma: usually found in elderly and there will be no history of trauma. X-rays shows osseous lesions which in long bones usually affects the metaphysis.', 'role': 'assistant'}]