Although cerebral arteriovenous malformation (AVM) is frequently seen in the anterior circulation, especially in the cerebral artery, it may also occur in the posterior circulation. Recently, the frequency of AVM in the posterior fossa is increasing, presumably because of improved diagnostic techniques, and including with neurotological examinations.
We recently examined a patient with posterior fossa AVM who had been diagnosed and treated as a case of cerebral infarction in another hospital because his main neurological deficit was hemiparesis. The patient's chief complaints were tinnitus and gait disturbance. Cerebellar signs ipsilateral to the hemiparesis including spontaneous nystagmus test, eye tracking test, optokinetic nystagmus test, auditory brainstem evoked response, gravinometry…etc, clearly revealed the presence of an AVM in the posterior fossa.
This case indicates that neurotological examinations are very useful in the diagnosis lesions in the posterior fossa, which used to be considered a black box.