Tumor-induced leg pain can be primary or secondary, characterized by strong pain, intermittent or persistent, fixed pain point and obvious pain at night. 1. Primary ones are osteosarcoma, which is a kind of malignant bone tumor, preferred in adolescents. The main symptom is localized pain, which is mostly persistent and gradually aggravated, and the pain is more obvious at night. It can also be accompanied by localized lumps, restricted joint movement and elevated local skin temperature. 2. Secondary metastatic cancer, such as lung cancer, breast cancer bone metastasis and so on. Bone metastasis leg pain is usually more intense, and there will be localized pressure pain, percussion pain and even pathological fracture symptoms, which are hard to bear.