Chondroblastoma is an uncommon benign neoplasm consisting of chondroid tissue mixed with more cellular tissue. In 98% cases it arise from the epiphysis. Osteoid osteoma is most commonly located in the proximal medial femoral coex just distal to the lesser trochanter. In long bones it is mostly located in the diaphysis followed by metaphysis. Ewings sarcoma usually arise from the diaphysis of long bones. Chondrosarcoma has a predilection for flat bones especially shoulder and pelvic girdles but can also affect diaphyseal poion of long bones.