<prompt> Commonest bone tumour isOsteoid osteomaCompact osteomaOsteoblastomaSolitary bone cyst  <response>: A. i.e. Osteoid ostoma 312 - Current diagnosis and Treatment 4thOSTEOID OSTEOMA Most common benign osteoid- forming tumor is the osteoid osteoma More common in male second decade Proximal femur is the most common site Dull aching pain is the most frequent symptom Characteristic x-ray finding - central lytic nidus The non ossifying fibroma of bone is the most commn benign tumor of bone and the solitary osteochondroma is the second most common 315- Current diagnosis Treatment - orthopedics Simple bone cysts are a common pseudotumor of bone and the most frequent cause ofpathologic fractures in children 320 CDT - orthopaedics 4th 