<prompt> Epiphyseal tumor before fusion of epiphysis:ChondroblastomaChondrosarcomaEwings sarcomaGiant cell tumor  <response>: MOST COMMON SITE OF PRIMARY BONE TUMORS Epiphyseal Chondroblastoma before physeal closure-purely epiphyseal OsteoclastomaGiant cell tumor after physeal closure in adults. Aicular osteochondroma. Clear cell chondrosarcoma. Ewings Sarcoma : is diaphysealmiddle of the shaft Chondrosarcoma: Occurs in bones formed with endosteal formation e.g.proximal femur, pelvis, proximal humerus, distal femur, scapula Usually metaphyseal. 