Unilateral cochleovestibular nerve compression syndrome in a patient with bilateral IAC osteoma.

Introduction: Osteomas of the internal auditory canal are rarely reported in the literature. Patients may complain of disabling symptoms of dizziness, hearing loss, and vestibular dysfunction. We report the case of a patient with bilateral osteomas of the internal auditory canal (IAC) associated with bilateral neurovascular compression mainly affecting the right cochleovestibular nerve (VIII) and right anterior inferior cerebellar artery (AICA).

Observation: This 75-year-old woman patient complained of disabling paroxysmal vertigo, typewriter tinnitus and hearing loss of the right ear. Temporal bone computed tomography showed bilateral osteoma arising from the posterior superior wall of the IAC. MRI sequences of the right VIII demonstrated compression by the right AICA against the inferior wall of the narrowed IAC. Treatment with oxcarbazepine allowed marked and lasting improvement of the patient's symptoms.

Conclusion: To our knowledge, this is the first description of an ipsilateral neurovascular compression syndrome of the VIII secondary to the presence of an osteoma narrowing the IAC.