Hypertrophic Pachymeningitis of the Internal Auditory Canal Induced by a Labyrinthine Fistula Complicated With Cholesteatoma

Hypertrophic pachymeningitis (HP) is defined by inflammation and thickening of the dura mater, and the etiologic factors are idiopathic or secondary to various conditions. To date, HP in the internal auditory canal (IAC) has rarely been reported. There have only been 3 reports of HP in the IAC. Magnetic resonance imaging showed enhancement of along the IAC and vestibule. After antibiotic treatment, enhancement was reduced with visible seventh and eighth nerves. The patient underwent tympanomastoidectomy. To our knowledge, this is the first case of HP associated with a labyrinth fistula complicated by cholesteatoma. We report MRI image with literatures.