Osteosarcoma of the skull base in a 15-year-old boy

Osteosarcoma is the most common primary malignant tumor of bone, occurring most frequently in the long bones of patients under the age of 20 years.1 Craniofacial sites account for fewer than 10% of all osteosarcomas, and the most common site in the head and neck is the mandible.2·3 The mean age at presentation for head and neck osteosarcoma is between 26 and 40 years.4 In children, osteosarcomas of the head and neck account for less than 1% of all head and neck malignancies and usually arise as secondary tumors after radiation therapy or chemotherapy,2 Other predisposing factors include retinoblastoma and Li-Fraumeni syndrome.4 Primary osteosarcoma of the craniofacial bones in children is even less common and typically presents as an expanding, painless swelling of 6 months' duration.3 Pathologically, these tumors range from 1 to 10 cm in size and demonstrate destruction of bone and surrounding tissues.2 A review of 22 cases of pediatric primary head and neck osteosarcoma showed a mean age at presentation of 12.2 years, with no gender predilection.3 Of these 22 cases, 2 involved osteosarcoma of the sphenoid sinus, while the rest were maxillomandíbular in origin. The 5- and 10-year survival rates for pediatric primary osteosarcoma of the head and neck have been reported as 63 and 52%.2 Although the role of adjuvant therapy has not yet been proven effective in osteosarcoma of the head and neck in children, it is frequently recommended because of the tumor's poor prognosis.6 Local recurrences are common and typically occur within 1 year of the original diagnosis.