Cholesterol granuloma of the petrous apex: CT diagnosis.

Cholesterol granuloma of the petrous apex is a readily recognizable and treatable entity that is more common than previously realized. Cholesterol granuloma grows slowly in the petrous apex as a mass lesion until it produces hearing loss, tinnitus, vertigo, and facial twitching. Twelve cases of cholesterol granuloma of the petrous apex are illustrated; ten of these are analyzed in detail, especially with respect to CT findings. A sharply and smoothly marginated expansile lesion in the petrous apex, isodense with brain and nonenhancing on CT, is in all probability a cholesterol granuloma. Cholesterol granuloma and cholesteatoma of the petrous apex are different lesions and treated differently. Cholesterol granuloma can be treated simply and effectively by drainage and permanent fistulization. Preoperative recognition by CT is important for planning proper treatment.