Hemorrhagic petrous apex cholesterol granuloma: clinical correlation with imaging.

C holesterol granulomas are commonly found in the petrous apex. Patients with cholesterol granulomas may present with headache or symptoms related to mass effect on adjacent structures and cranial nerves, and cholesterol granulomas often may be an incidental finding on neuroimaging for other reasons. Although these lesions may remain dormant for many years, they can also suddenly enlarge, with expansion and subsequent remodeling of the petrous apex. The most common explanation for expansion or enlargement of cholesterol granuloma is thought to be internal hemorrhage. The ability to identify cholesterol granuloma is crucial, since in the acute setting it can simulate an enlarging aggressive lesion.