This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ohopedics Oncology, Subject name: Orthopaedics
Epiphyseal tumor before fusion of epiphysis: 
Select and explain. 
A. Chondroblastoma, B. Chondrosarcoma, C. Ewing's sarcoma, D. Giant cell tumor
A: Chondroblastoma
Answer: A: Chondroblastoma 
Explanation: MOST COMMON SITE OF PRIMARY BONE TUMORS (Epiphyseal) Chondroblastoma (before physeal closure)-purely epiphyseal Osteoclastoma/Giant cell tumor (after physeal closure in adults). Aicular osteochondroma. Clear cell chondrosarcoma. Ewing's Sarcoma : is diaphyseal(middle of the shaft) Chondrosarcoma: Occurs in bones formed with endosteal formation e.g.proximal femur, pelvis, proximal humerus, distal femur, scapula Usually metaphyseal.