Endoscopic management of a giant cholesterol cyst of the petrous apex.

Giant cholesterol cyst (GCC) of the petrous apex is a rare clinical entity. This benign cystic lesion can cause neurologic deficits and vascular compromise by persistent growth and progressive bone destruction. Magnetic resonance imaging studies of GCC show the lesions to be hyperintense on T(1)-weighted sequences with progressively lower signal intensities on the first and second echoes of T(2)-weighted sequences. These findings are relatively specific for GCC, permitting a narrow differential diagnosis. The goal of surgery is to provide adequate drainage with the creation of a permanent fistula. The classic approaches to these lesions are the posterior fossa craniotomy and the middle fossa extradural craniotomy. The translabyrinthine approach provides wide exposure at the expense of cochlear and vestibular function. The transsphenoidal approach provides adequate drainage with hearing preservation and no craniotomy. The endoscopic, endonasal transsphenoidal approach to a 2.5 cm GCC of the petrous apex accomplished complete drainage with the creation of a fistula. Advances in endoscopic technique and instrumentation facilitated the addition of the approach to the surgeon's armamentarium. In selected cases, this approach provides adequate surgical exposure with minimal morbidity.