Anterior epitympanic cholesteatoma with facial paralysis: a characteristic growth pattern.

Epitympanic cholesteatoma may involve the facial nerve at several anatomic locations resulting in functional impairment. The most common site of nerve compression is the middle-ear segment where the nerve is frequently devoid of bony covering. In five patients with facial palsy due to epitympanic cholesteatoma, a characteristic pattern of growth was recognized in which the cholesteatoma traversed the anterior epitympanum rather than taking the more common posterior route. Extension anteromedial to the head of the malleus leads to compression of the facial nerve in the region of the geniculate ganglion at the level of the middle cranial fossa floor. The most probable pathogenesis of this lesion is extension of disease along the embryologic course of either the saccus anticus or the anterior saccule of the saccus medius. Management of these lesions is surgical and may require, in addition to mastoidectomy with anterior and/or posterior atticotomy, middle fossa craniotomy and/or partial removal of the labyrinth for complete excision.