There are two types of bone tumors, primary and secondary. Primary bone tumors are divided into tumor-like lesions, benign tumors and malignant tumors; secondary tumors are malignant tumors from other tissues or organs of the body that metastasize to the bone, and their incidence is 30-40 times higher than that of primary malignant tumors of bone. Among benign tumors, osteochondroma is the most common, followed by giant cell tumor of bone, chondrosarcoma, osteoma, ossifying fibroma, hemangioma, osteoid osteoma, mucinous fibroma of cartilage, osteoblastoma, chondroblastoma, and non-ossifying fibroma. Most of these tumors occur in the lower femur and upper tibia. Some tumors, such as chondrosarcoma, occur in the hand bone, osteoma, in the skull and jaw bone, and giant cell tumor, in addition to the femur and tibia, also occur in the vertebrae, sacrum, and radius. Among malignant tumors, osteosarcoma is the most common, followed by chondrosarcoma, fibrosarcoma, Ewing sarcoma, malignant giant cell tumor of bone, chordoma, malignant lymphoma, malignant fibrous histiocytoma, and the rest are rare, while individual tumors such as Ewing sarcoma are found in the pelvis, myeloma in the trunk bone, and chordoma in the sacrum and the base of the skull. Among the aneurysmal lesions, fibrodysplasia is the most common, followed by isolated bone cysts, eosinophilic granulomas, and aneurysmal bone cysts. The most common sites are the femur and tibia, followed by the humerus, skull, and jaws. The different characteristics of benign and malignant bone tumors are as follows: 1 Pain: Pain is an important symptom of malignant bone tumors, which is intermittent at the beginning of the disease, but later develops into persistent and obvious at night. In the late stage, the pain increases and affects work, rest and sleep, and strong analgesics are needed. Benign tumors have a slow course with little or no pain. 2. Growth rate: Gradual growth of mass is the basis for the diagnosis of bone tumor. Benign tumor masses grow slowly and often go undetected, or are occasionally detected but cannot tell when they first started. Enlarged masses do not affect the surrounding tissues much and rarely interfere with joint movement. Malignant bone tumors have a short history of rapid growth, increased skin temperature and varicose veins in enlarged tumors, and joint swelling and limited motion in long bones and epiphyses. Pathological fracture: Pathological fracture caused by minor trauma is often the first symptom of benign bone tumor, but also a common complication of malignant bone tumor and metastatic bone cancer. It has the same swelling, pain, deformity and abnormal activity as simple traumatic fracture. 4 Systemic symptoms: In the advanced stage of malignant bone tumor, there may be anemia, emaciation, loss of appetite, weight loss and fever. Most of the distant metastases are hematogenous metastases, and occasionally lymph node metastases are seen. Benign bone tumors do not have the above characteristics.