Postirradiation Osteosarcoma Arising from Femoral Metastasis of Hepatocellular Carcinoma: A case report

Radiation associated sarcomas are uncommon, constituting less than 5% of all sarcomas and generally associated with a poor prognosis. We are reporting a case of an 82-year-old male who had a history of hepatocellular carcinoma associated with a solitary metastasis over the proximal femur. The metastatic bone lesion was stabilized by a static interlocking nail and augmented with bone cement. Postoperative radiotherapy was given in divided dose in 3 years to the whole femur with a total dose of 79 Gy. No evidence of tumor recurrence or progression was found at the subsequent follow-up. However, bone destruction accompanied with a huge soft tissue mass developed over the irradiated area five years later. Intra-lesional excision and reconstruction with a tumor prosthesis were performed. The pathologic result revealed post-irriadiation osteosarcoma instead of local recurrence of metastatic carcinoma.