Osteosarcoma has some chance of misdiagnosis if the diagnostic modality of imaging is based on a pathologic diagnosis, which has a minimal chance of misdiagnosis. Osteosarcoma is a malignant tumor of the bone tissue that is commonly detected by imaging screening because of pain in the bone tissue with movement. The typical periosteal reaction of osteosarcoma is called Codman’s triangle, so the disease is suspected when it is detected on imaging. However, the imaging diagnosis is not 100% accurate, and all confirmatory diagnoses are based on pathologic diagnosis. The chance of misdiagnosis in pathologic diagnosis is very low. Surgical treatment of osteosarcoma before systemic metastasis is still ideal, and the combination of surgery and chemotherapy can effectively improve the five-year survival rate of patients.