Metastatic osteosarcoma to the liver after treatment for synovial sarcoma: A case report

Metastatic osteosarcoma most commonly affects the lungs and other bones. Hepatic metastasis at the time of diagnosis is extremely rare. A 14-year-old boy with synovial sarcoma of the left popliteal fossa was treated with surgical resection, radiotherapy for microscopic residual disease, and 1 year of chemotherapy (vincristine, cyclophosphamide, dactinomycin, and doxorubicin). Approximately 10 years after the initial diagnosis, a secondary osteosarcoma developed in the left proximal tibia. Computed tomography at presentation showed bilateral pulmonary metastases and large ossified nodules in the liver that demonstrated abnormal avidity on Tc-99m MDP bone scan indicating hepatic metastasis. Despite chemotherapy (cisplatin, ifosfamide, high-dose methotrexate, and dacarbazine), the patient died of progressive disease 4 months after the diagnosis of the second cancer. Hepatic metastasis was found at the time of diagnosis of a secondary osteosarcoma and manifested as ossified nodules. The risk of radiation-induced osteosarcoma should always be considered in decisions about treatment for soft-tissue sarcoma.