Let's briefly describe osteosarcoma, which is a malignant tumor of the bone, most commonly found in adolescents and young adults, typically occurring near the proximal end of the tibia, the distal end of the femur, or the proximal end of the humerus, mainly growing at the epiphyseal ends.

In the early stages, patients show no symptoms, with the most common symptom being pain, usually discovered in the middle to late stages. This pain tends to be persistent and is most pronounced at night. Some patients may also have a local mass. Osteosarcomas are highly prone to early lung metastases. Additionally, the surface skin temperature may increase, veins may become distended, and there may be a presence of cachexia as the disease progresses, leading to severe thinness and weakness in the body. The primary diagnostic basis is radiographic examination, which might show unique signs such as Codman’s triangle under sun-ray exposure, indicative of osteosarcoma. If the radiographic signs are not typical, further differentiation can be done using CT scans or MRI. The most crucial matter is surgical biopsy for a definitive diagnosis, mainly based on the postoperative pathology. Intraoperative measures like cryosurgery can be performed. Upon discovery, limb amputation is generally recommended, although limb-sparing surgeries can be considered, involving techniques like resection followed by reimplantation or prosthetic implantation. Overall, the prognosis is typically poor, but with the rapid advancement in chemotherapy, the five-year survival rate can improve somewhat, generally around 50%.