Codman's triangle is a feature of -: (A) Osteosarcoma, (B) Osteochondroma, (C) Osteoid osteoma, (D) Chondrosarcoma
Answer is A. A Codman triangle develops when a poion of periosteum is lifted off of the coex by tumor, pus, or hemorrhage at a leading edge . This aggressive form of periosteal reaction is commonly seen in osteosarcomas and occasionally with infection and metastases.