The most frequent type of cerebellar infarcts involves the posterior inferior cerebellar artery (PICA) and superior cerebellar artery territories. Bilateral symettrical cerebellar infarcts are extremely rare. The etiology of this infarct pattern has not been shown clearly. It is postulated that bilateral PICA infarcts are caused by the stenosis of PICA which emerges from the left vertebral artery that supplies the blood for both cerebellar hemispheres.

A 42-year old male patient came with complaints of headache, loss of balance, vertigo, nausea-vomiting and diplopia. On his neurological examination, there was nistagmus and diplopia on both horizontal gaze directions. His cerebellar tests were minimal deficient on the left side and the patient had an ataxia to the left side. His cranial MR revealed bilateral PICA infarct, and his digital substraction angipgraphy (DSA) showed that his vertebral artery was stenosed from its point of origin. The etiological cause was thought to be intracranial vertebral artery occlusion with a baseline insitu atherosclerosis, in the presence of branches having their origin from one side and going to both PICA territories. The bilateral PICA infarct case,which is a rare clinical presentation, was evaluated with the help of the literature and probable pathogenesis was hypothesized.