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What is 15 year old boy presented with a mass in the distal femur. X-ray from the lesion showed features of Codman's triangle and Sunray appearance. The diagnosis is: and explain in detail?
Codman's triangle and Sunray appearance are characteristic radiological findings in osteosarcoma. When the tumour elevates the periosteum of bone, a gap occurs between periosteum and bone, where the gap is elevated, bone is formed, creating a triangular shape on radiographs. Ref: Apley's system of ohopaedics and fractures;8th/185; Essential ohopedics by Maheshwari 3rd/219, 222.