A Message from a Narrowed Internal Auditory Canal in a Patient with a Hyperpneumatized Petrous Bone.

Hyperpneumatization of the temporal bone (HPTB) is a rare finding, and its clinical impact is poorly described in literature. We report the case of a 34-year-old woman with no previous otologic condition, complaining of paroxysmal vertigo and right pulsatile tinnitus shortly after a first scuba diving session. Clinical neurotologic assessment found a right vestibular impairment. Cranial tomodensitometry showed a bilateral hyperpneumatization of the petrosal air cell system. Brain magnetic resonance imaging to rule out any retrocochlear pathology was normal, although the cochleo-vestibular nerve (CVN) appeared to be over lengthened in a narrowed internal auditory canal (IAC), especially on the right-hand side. Pain was alleviated by administration of a low-dose anti-epileptic drug. The clinical, neurological, and radiological findings evoked a right vestibulopathy generated by a limited compression of the CVN; HPTB appeared to contribute to the narrowing of the IAC, especially on the right-hand side.