Extracranial skull base chondrosarcoma.

Chondrosarcoma of the skull base is a rare neoplasm. The most common presenting symptoms are hoarseness, dysphagia, and diplopia, which is associated with palsies of cranial nerves X, IX, and VI. The temporal bone is the most common site of tumor origin, followed by the sphenoid bone. These tumors must be differentiated from chordoma, chondroid chordoma, osteogenic sarcoma, enchondroma, and meningioma. Diagnosis is made by patient history, radiologic imaging, and biopsy. The treatment is surgical excision followed by radiation therapy. Five-year survival rates for grades I, II, and III are 90, 81, and 43%, respectively.