Adult-Onset Labyrinthine Fistula as a Sign of Undiagnosed Bilateral Congenital Cholesteatoma

Objective. Bilateral congenital cholesteatoma is a very rare condition. We describe the first case of an adult patient presenting with bilateral congenital cholesteatoma with labyrinthine fistula. Case report. We present a 34-year-old woman of bilateral congenital cholesteatoma with labyrinthine fistula, inducing leftsided mixed conductive-sensorineural hearing loss and vertigo, subsequently accompanied by right-sided conductive hearing loss. Otoscopic examination and computed tomography scan revealed bilateral congenital cholesteatoma with a fistula in the left lateral semicircular canal. Tympanomastoidectomy was performed, and both congenital cholesteatoma were completely removed, and membranous fistula of the left lateral semicircular canal was covered with a graft. Conclusion. Congenital cholesteatoma is usually detected in childhood not but in adulthood. With delay in diagnosis, the risk of cholesteatoma complications increases. Greater attention should be paid to complications such as labyrinthine fistula resulting from long-term exposure to congenital cholesteatoma in adults.