Rare presentation of an arteriovenous malformation within the internal auditory canal

While cerebral arteriovenous malformations (AVM) are common, a presentation of this vascular lesion involving the internal auditory canal (IAC) is rare. We describe a case of an un-ruptured AVM within the right IAC of a 55-year-old male who presented following a whiplash injury and left-ear (contralateral to the lesion) unilateral non-pulsatile tinnitus. On magnetic resonance imaging (MRI), an incidental atypical linear enhancement suspicious for a vascular lesion within the right IAC was identified and investigated further using magnetic resonance angiography and venography (MRA/MRV), which illustrated serpentine flow voids that confirmed the presence of an AVM. Given the patient's intact hearing and rare location of the AVM, treatment options including watchful waiting, stereotactic radiosurgery, embolization, and microsurgery were discussed, of which observation was chosen