Congenital cholesteatoma extending into the internal auditory canal and cochlea: a case report.

We report here on a case of congenital cholesteatoma that extended into the internal auditory meatus and cochlea. A 17-year-old boy underwent surgery for a very large cholesteatoma, which was discovered behind an intact tympanic membrane. Pure tone audiometry revealed an unresponsive ear. High resolution temporal bone computed tomography showed perilabyrinthine extension with its absence in the vestibular area, and destruction of the bony cochlea at the basal turn, the tegmen and the posterior cranial fossa. Magnetic resonance imaging revealed no intracranial extension. Surgical exploration of the middle ear and the mastoid cavity revealed that both the vestibule and the basal turn of the cochlea were filled with a noninfected cholesteatoma. The cholesteatoma extended into the internal auditory meatus through translabyrinthine destruction; it extended into the basal turn of the cochlea through the infralabyrinthine route. The bony segment of the facial nerve canal demonstrated near total dehiscence. The cholesteatoma was removed by the transotic approach. Congenital cholesteatoma is characterized by no specific history. Therefore, early detection of this malady can be challenging, but it is important to prevent such complications as were observed in this reported case.