Chondrosarcoma of the base of the skull is a rare clinical entity. In an extensive review of the world literature, Berkman and Blattl reported only 16 chondrosarcomas in a total of 113 case reports of cranial and intracranial cartilaginous tumors. The sphenoid bone is the commonest site of such neoplasms.In general, chondrosarcomas have been regarded as almost totally radioresistant, and no instance of successful radiation treatment of a sphenoid chondrosarcoma has so far been reported. Publication of this case report, therefore, seems warranted.The patient, a 49-year-old Caucasian female, was referred for radiotherapy consultation initially in December, 1965, with a biopsy-proven recurrence of chondrosarcoma of the sphenoid sinus and base of the skull.In the Fall of 1958, she had first noticed a full feeling in the left side of her nose. Symptoms increased slowly for about eight months, and at that time nasCiI examination revealed a tumor in the region of the left middle turbinate and left inferior meatus. There was no evidence of cranial nerve involvement, and the lesion was deemed operable. Through an anterior rhinotomy, a radical exenteration of the left ethmoid and sphenoid area was performed. This included the middle and inferior ethmoid air cells (both anterior and posterior groups,), the medial and posterior walls of the left maxillary sinus and also, the superior middle and inferior turbinates. It extended upward to the cribiform plate. The erQded anterior wall of the sphenoid was removed, and the cavity of the sphenoid sinus was found to be filled with tumor. Although all gross tumor was resected, a marginal section from the region of the cribiform plate showed the presence of chondrosarcoma in this area as well.The patient was followed at intervals of four to six months and remained perfectly well for the succeeding s,ix years. In December, 1965, a new mass was found on the posterior wall of the nasopharynx, and a biopsy again revealed a well differentiated low-grade chondrosarcoma (Fig. 1). TomQgraphy (Fig. 2-A) confirmed a bone destroying lesion with irr,egular ossification of bQth anterior and posterior walls of the sphenoid sinus with a probable breakthrough into the pituitary fossa and nasopharynx.Functional inquiry and clinical physical examination revealed few findings of note other than as mentioned above. Specifically, she denied any pain, disturbance of vision Otr weight loss. Her general condition was excellent. No cranial nerve palsies were found, and her visual fields were not impaired. No lymph nodes or other soft tissue Qr bone metastases were identified.The primary lesion, a 4 to 5 cm diameter mass, was clearly visible on the roof and posterior wall of the nasopharynx. It was covered by mucosa, but protruding 1 to 2 em
