Aneurysmal bone cyst is now recognized as a distinct clinicopathologic entity. It has characteristic clinical, radiologic, and pathologic feactures. The two modalities of treatment are surgical resection or curettage and radiotherapy: recurrence rates with each modality are discussed. A case report of an aneurysmal bone cyst presenting in the sphenoid sinus and treated with the compbined modalities of irradiation and surgical curettage is presented.