Osteosarcoma of extragnathic craniofacial bones.

Osteosarcomas of extragnathic craniofacial bones--those bones of the skull excepting the jaw bones--are rare lesions, constituting fewer than 2% of all osteosarcomas. In our series of 21 patients (12 male and 9 female), the ages ranged from 6 to 77 years, and 10 patients were in the third or fourth decade of life. At least six patients had predisposing conditions: Paget's disease of bone in three and prior regional irradiation in three. Most of these tumors were high-grade lesions, and most were extensive when treated. There were 11 osteoblastic, 6 fibroblastic, and 1 small cell variant; 2 lesions had features resembling malignant fibrous histiocytoma. One tumor, originally interpreted as grade 4 osteosarcoma, was unavailable for variant classification. Surgical removal, irradiation, and chemotherapy were used in treatment, alone or in combination. Only two patients survived 5 years, and one of these patients died of her disease after 65 months. Almost half of our patients died within 1 year after diagnosis. The one long-term survivor (12 years) underwent a radical surgical procedure when her tumor was small; this was the only patient in this series who had a low-grade lesion. Because of the characteristics described, osteosarcoma of extragnathic craniofacial bones must be considered a distinct disease.