Differentiation of benign and malignant bone tumors: benign bone tumors: 1. (Age) mostly adults 2. The tumor is solid, no pressure pain, clear boundary, no significant increase in skin temperature, no superficial venous anger, generally does not affect the adjacent joints 6.(Laboratory test) No change 7.(X-ray) The tumor is confined to bone tissue, clear and neat boundary, visible around reactive sclerotic bone, swelling change around the foci of destruction, little periosteal reaction 8.(Pathology) The degree of differentiation of tumor cells Malignant bone tumor: 1.(Age) Mostly 2, (growth rate) rapid growth 3, (growth mode) invasive growth, often metastasis 4, (symptoms) late stage can appear fever, loss of appetite, wasting and other systemic symptoms. 5. (Signs) Diffuse swelling of the mass, pressure pain, unclear boundary, elevated skin temperature, superficial venous anger, often affecting the adjacent joints. 6. When malignant bone tumor shows extensive bone destruction or extensive bone metastasis, blood calcium is elevated, alkaline phosphatase is elevated in osteosarcoma or osteogenic disease, and acid phosphatase is elevated in prostate cancer bone metastasis. 7. 8.（Pathology）Tumor cells have low differentiation and abnormal nucleus.