[A case of repetitive cerebellar ataxia with persistent primitive trigeminal artery]

We reported a case of 40 year-old-male, with the persistent primitive trigeminal artery (PPTA), who had exhibited transient dysarthria and gait disturbance since he was 30 years old. The symptoms gradually became aggravated in both frequency and duration. The results of the angiography showed that hypogenesis of bilateral vertebral artery and PPTA originated from the left internal carotid artery and joined to the upper portion of the basilar artery. Single photon emission computed tomography (SPECT) revealed no abnormality, whereas those of MRI showed PPTA compressing the left ventral part of the pons. It seemed probable that transient cerebellar ataxia occurred with transient compression of the ventral part of the pons, containing the pontocerebellar fibers, by the expansion of the lumen of PPTA.