A case of osteosarcoma occurring in the mandible of 48-year-Dld man was presented. At first visit, clinical diagnosis was osteomyelitis, and the diagnosis of osteosarcoma was done by biopsy.He underwent radical operation (hemimandibulectomy and reconstruction with D-P flap), before and after which high-dose methotrexate therapy (100mg-300mg/kg) was carried out.There is no evidence of recurrence till now.
