Artery of Percheron infarct with multiple cranial nerve palsies and Horner Syndrome.

Purpose: To report a case of a rare stroke variant involving the artery of Percheron leading to ocular motility compromise. Observations: A 65-year-old man presented to the neuro-ophthalmology clinic with multiple cranial nerve palsies and Horner Syndrome. He was three weeks post-thrombolytic therapy to treat an ischemic stroke, and his pertinent medical history consisted of hyperlipidemia and macular degeneration. On physical exam, the patient experienced bilateral vertical gaze paresis, incomplete left Horner syndrome, right-sided cranial nerve VI palsy, and partial left-sided cranial nerve VII palsy. Based on the infarction patterns demonstrated on MRI, the patient was diagnosed with an artery of Percheron infarct. Conclusions and importance: The artery of Percheron is a rare variant of posterior cerebral circulation that supplies both paramedian thalamic zones in addition to variably supplying the midbrain. Overall, this case highlights the importance of considering rare anatomical variants when working up ophthalmic deficits in a stroke patient. Early diagnosis can lead to adequate therapy and prevent complications in the future.