Bilateral cholesterol granuloma of the skull base: case report and review of the literature.

A unique case of bilateral cholesterol granuloma of the skull base and its treatment is presented. Cholesteatoma, a pathological entity often confused with cholesterol granuloma, is differentiated from cholesterol granuloma. Cholesterol granuloma is not rare. This tumor seems to derive from an inflammatory process at the skull base that results in bony erosion surrounding a cyst wall of inflammatory tissue. Neurological abnormalities reflect the location of the tumor in relation to the brain stem. Radiographically, the cyst wall enhances with the administration of i.v. contrast agent, and the center of the lesion is isodense with brain on computed tomography, unlike cholesteatoma. Magnetic resonance imaging characteristics are currently being defined. At operation, cholesterol granuloma consists primarily of a viscous fluid within a capsule of inflammatory tissue. Treatment requires establishing a pathway for drainage of the granuloma. The advantages of transsphenoidal, transclival drainage of such lesions are outlined.