A Case of Cholesteatoma from the Middle Ear diagnosed as a Cerebellopontine Angle Tumor 17 Years after the Radical Mastoidectomy

Intracranial extension of acquired cholesteatoma from the middle ear is rare. A 49-year-old man has taken a radical mastoidectomy for cholesteatoma with otitis media, following right facial-hypoglossal anastomosis 17 years ago. On March, 1998, he was admitted with complaints of convulsive attacks following severe headache and high fever for 2 weeks. Neurological examination on admission revealed mild limb ataxia and VIIth., VIIIth., XIIth.nerve palsies in the right side. MRI demonstrated a mixed intensity mass without enhancement effect located on the cerebellopontine angle and the petrous bone in the right side. Tumor was totally removed by the right lateral suboccipital craniectomy. The pathological examination showed typical cholesteatoma. The postoperative course was uneventful. Seventeen cases of acquired cholesteatoma extending to the intracranial space were reviewed on the literature including ours, only 4 of whom had long interval more than 8 years to last intracranial operation. In the present case, it appears to take a long time to be detected as a cerebellopontine angle tumor not only because no progressive symptoms revealed before the second operation but this tumor had the benign "slow growth" characteristics, although the tumor might have already extended to the intracranial space at the initial radical mastoidectomy.