primary bone tumor locations malignant v3 Overview Ewing Sarcoma Introduction anaplastic small blue cell tumor neuroectoderm origin involves an 11;22 translocation boys < 15 has highest incidence most often seen in diaphysis of long bones, pelvis, scapula, and ribs Evaluation layered "onion-skin" deposition of bone Prognosis, Prevention, and Complications early metastasis responsive to chemotherapy Chondrosarcoma Introduction malignant cartilaginous tumor seen in men 30-60 years most commonly involves the central skeleton may occur de novo or from progression of osteochondroma Evaluation expansile glistening mass located in the medullary cavity Osteosarcoma (osteogenic sarcoma) Introduction tumor of osteoblasts most common primary malignant tumor of bone commonly found in the metaphysis of long bones e.g. distal femur or proximal tibia risk factors Paget disease of bone results in onset in elderly bone infarcts radiation familial retinoblastoma Rb mutation results in onset before third decade Evaluation histology large pleomorphic cells producing increased osteoid Radiograph Codman's triangle or sunburst pattern from elevation of periosteum from the cortical bone Prognosis, Prevention, and Complications poor prognosis Bone Metastasis Introduction typically result in osteolytic lesions exception is prostatic carcinoma produces osteoblastic lesion