Bilateral metachronous osteosarcoma of the mandibular body: a case report.

Osteosarcoma of the jaw (JOS) is a rare phenomenon constituting 5% to 13% of all cases of osteosarcoma (OS). JOS has histological features similar to OS, but the biological behavior is different. The chief complaint of patients with long bone OS is pain, whereas patients with JOS usually have painless swelling as the first sign. OS may affect multiple sites. Multifocal or multicentric osteosarcoma is usually defined as metachronous (new tumors developing after initial treatment) or synchronous (multiple lesions at presentation) without pulmonary metastases. The incidence of this entity has been reported to be between 1% and 10% of all cases of OS. A 27-year-old man presented with bilateral metachronous osteosarcoma as painful swellings in the mandibular body. He was treated with a mandibulectomy and chemotherapy. Therefore, the physician should be aware that osteosarcomas can occur in different sites as true multicentric or metastatic lesions. (Chang Gung Med J 2011;34(6 Suppl):66-9)