Osteosarcoma of the Skull Base after Radiation Therapy in a Patient with McCune-Albright Syndrome: Case Report.

Sarcomas of the skull base occurring in the field of prior radiotherapy are rare; only a few have been reported in the English literature. We report a fatal osteosarcoma of the skull base arising in a patient with McCune-Albright syndrome and severe fibrous dysplasia of the skull base 22 years after radiation therapy for a pituitary adenoma. This malignancy fulfills Cahan's criteria for a radiation-induced tumor in that it arose in the radiation field of a pituitary adenoma with a latency of 22 years. The literature on radiation-induced sarcomas of the skull base is reviewed, and the predisposition of patients with isolated fibrous dysplasia or McCune-Albright syndrome to develop radiation-induced tumors is discussed. Although the risk of radiation-induced malignancy is low in the general population, special consideration should be given when contemplating the use of radiotherapy for benign disease in patients with McCune-Albright syndrome or isolated fibrous dysplasia.