A case of acquired petrous cholesteatoma associated with insidious middle ear infection treated by staging the surgical procedures.

Surgical treatment of petrous cholesteatoma is difficult, especially in infected cases, since it often involves vital structures. We report the case of a patient successfully treated for an infected petrous cholesteatoma by staging the surgical procedures to reduce the risk of intracranial complications. The patient, a 53-year-old man, was referred to our hospital because of vertigo during coughing or strenuous effort. The left side mastoid cavity was open to the external ear canal and wholly covered with cholesteatoma epithelium with purulent discharge. The superior basal turn of the cochlea, superior and posterior semicircular canals, and roof of the internal auditory canal were eroded. Conservative treatment was not effective in eradicating the otorrhea. Four weeks after the first operation (radical mastoidectomy), the second operation was conducted following a combined middle cranial fossa and transmastoid approach. The postoperative course was uneventful. Normal facial nerve function was preserved and unsteadiness disappeared, but hearing could not be preserved. The MRI examination, performed one year after surgery, did not reveal any evidence of residual cholesteatoma.