Osteoblastic Extraosseous Osteosarcoma of the Neck

Extraosseous osteosarcoma as a primary tumor of the neck is exceedingly rare, with only a few cases reported to date. The most appropriate therapy is still under investigation. We report a case of an aggressive, right-sided, advanced-stage extraosseous osteosarcoma in a female patient. A 48-year-old woman presented with a right-sided infra-parotid mass encompassing neck regions II and III, measuring over 6 cm in craniocaudal diameter. She was initially treated by wide surgical resection. The definitive histopathologic diagnosis was osteoblastic extraosseous osteosarcoma. Computed tomography at initial presentation did not show signs of tumorous growth in other areas. The patient was treated with adjuvant chemoradiotherapy postoperatively. A local recurrence with intraspinal propagation was noted 4 months after surgery, and a second surgical attempt was made to remove the tumor. The disease recurred in the neck and spine 3 months after the second surgical procedure, and a final unsuccessful attempt at reducing the tumor mass was performed. The tumor site was reirradiated. The patient died of local disease propagation 3 months later. Extraosseous osteosarcoma of the neck is an extremely rare tumor, distinct from primary osteosarcoma of the bone, with a high rate of local recurrence and poor prognosis in advanced disease.