Best known for their epiphyseal origin in long bones, giant cell tumors of bone only rarely involve the cranial vault. Of the exceptional cases that do, virtually all arise in the sphenoid or temporal bones. The predilection for giant cell tumors to arise here has been related to the unique embryology of the sphenoid and temporal bones. Unlike the remaining osseous components of the cranial vault, the sphenoid and temporal bones share with long bones of the skeleton an origin via endochondral bone formation. Fewer than 40 cases of giant cell tumor of the sphenoid bone have been reported, with most occurring in the third and fourth decades of life (112,113). Beginning in the floor of the sella, these are destructive lesions that spread laterally and inferiorly as cohesive soft tissue masses. Destruction of the dorsum sellae is typically an early radiologic feature—one eventually followed by destruction of the sphenoid wings, petrous apex, and clivus. Headaches, visual loss, and cranial nerve palsies are the most frequent presenting symptoms; pituitary insufficiency is rarely a feature. In the past, most cases were treated with surgical resection followed by radiation therapy. More recently, particularly with the evolution of skull-base surgery, as well as the concern of radiation-induced sarcomatous degeneration, there has been increasing emphasis on radical resection as the sole form of therapy (112).
Radiation therapy is reserved for incompletely excised and recurrent tumors, in addition to those with obvious malignant history. The prognosis is both variable and unpredictable. In some cases, long-term quality survival is achieved; however, in others, progressive or recurrent disease is accompanied by significant disability or death.
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