Facial nerve and medially invasive petrous bone cholesteatomas.

Eight patients with extensive petrous bone cholesteatomas that invaded the labyrinth and fallopian canal are presented. The eight cases are added to a tabulation of prior literature reports to elucidate concepts of routes of extension of medially invasive temporal bone cholesteatoma. Medially invasive petrous bone cholesteatoma develops insidiously, often without symptoms other than facial palsy and/or unilateral deafness. Typically, a history of chronic ear disease can be obtained. While hearing is unlikely to be preserved in this group of patients, facial nerve function can usually be preserved, and a facial nerve graft was not necessary in our series. Acute facial nerve palsy or facial nerve paresis progressing to palsy in patients with a history of chronic ear disease should be studied radiographically for petrous bone cholesteatoma, even if there is no physical evidence of cholesteatoma.