Conventional osteosarcoma of the mandible successfully treated with radical surgery and adjuvant chemotherapy after responding poorly to neoadjuvant chemotherapy: a case report

Osteosarcoma, the most common primary bone malignancy, has an extremely poor prognosis and a high rate of local recurrence and distal metastases. Because osteosarcomas of the head and neck region are rare, accounting for less than 10% of all osteosarcoma cases, limited information is available about their treatment and prognosis. Because of the high rate of distal metastases associated with extragnathic osteosarcoma, surgery combined with chemotherapy is currently considered essential in its treatment. However, the role of chemotherapy has not been well elucidated in the treatment of head and neck osteosarcoma because of the rarity of this condition. In this report, we present the case of a 58-year-old Japanese woman with osteosarcoma of the mandible that was treated with radical surgery combined with neoadjuvant and adjuvant chemotherapy. Because the tumor showed rapid growth during neoadjuvant chemotherapy, neoadjuvant chemotherapy was suspended and surgical resection was performed, followed by adjuvant chemotherapy. No evidence of local recurrence and distal metastasis was found 14 months after initial treatment. Local control is considered a principal prognostic factor for head and neck osteosarcoma. Wide surgical excision should be considered a primary goal even during neoadjuvant chemotherapy, especially in cases that respond poorly to neoadjuvant chemotherapy.