Osteosarcoma of the Skull Base in the Pediatric Population: A Case Report and Literature Review

Objective: A comprehensive review of the literature of pediatric osteosarcoma of the skull base and a report of a new case.

Study Design: A literature review and case report.

Methods: A review of the MEDLINE database (1950-May 17, 2015) to identify all cases of pediatric osteosarcoma of the skull base. Reports written in a language other than English or without an abstract available were excluded from review. Additionally, a new case is presented.

Results: A total of six cases of pediatric osteosarcomas of the skull base were identified and found to meet inclusion criteria. Of these, 50% were associated with prior radiation therapy. In the three de novo cases of pediatric osteosarcoma of the skull base, age at the time of presentation ranged from 10–14 years old. The presenting symptoms were visual changes and ocular symptoms in two patients, and multiple cranial neuropathies in the third patient. Two of the patients’ tumors were deemed unresectable and treated with chemoradiation therapy. One patient was treated with neoadjuvant chemotherapy followed by open transnasal resection with positive margins and adjuvant radiation therapy. At the times of publication, all three children were without residual or recurrent disease, with 3–18 months of follow up reported. A 9-year-old male presented with unilateral epistaxis, epiphora, and proptosis. Visual acuity and cranial nerves were intact, and exam revealed a mass filling the left nasal cavity. CT and MRI scans revealed a 5.2-cm expansile mass extending from the left ethmoid and frontal sinuses into the nasal cavity, with erosion of the lamina papyracea and extension into the extraconal space. There was no extra-axial involvement. Biopsy revealed high-grade osteoblastic osteosarcoma. Neoadjuvant chemotherapy with cisplatin, doxorubicin, and methotrexate was initiated. Endoscopic resection with image guidance was then undertaken, with negative margins achieved. MRI performed post-operatively showed no gross residual tumor. The patient completed his chemotherapy post-operatively. Genetic analysis revealed Li-Fraumeni syndrome. Five and a half months after surgery, the patient continues to do well with no visual complaints, cranial nerve deficits, or evidence of recurrent disease.

Conclusion: Osteosarcoma of the skull base is an uncommon entity, and pediatric cases are exceedingly rare. In the absence of a history of radiation, genetic analysis should be pursued to rule out hereditary disorders. Neoadjuvant chemotherapy followed by surgical resection to clear margins is the treatment modality of choice, when possible. The case presented here represents the first de novo pediatric osteosarcoma of the skull base to be successfully resected via an entirely endoscopic approach, and the first to be treated without the use of radiation therapy. When such aggressive malignancies involve the skull base and place critical structures at risk, approaches to treatment must be tailored to the individual patient and the tumor’s anatomical boundaries. Endoscopic approaches, when feasible, offer the possibility for cure while minimizing post-surgical recovery and morbidity.