A Highly Uncommon Variation of “Top of the Basilar” Syndrome

Stroke is a leading cause of death and acquired disability worldwide. Top of the Basilar Syndrome (TOBS), is a relatively uncommon subtype of stroke, and it has a wide spectrum of clinical presentations (abnormalities of alertness, inversion of the sleep–wake cycle, and abnormal oculomotor or pupillomotor functions) due to anatomic variations of posterior circulation, raising diagnostic challenges. In this case study, A 78-year-old man was admitted to our hospital with sudden-onset hemi paralysis and stupor followed by central facial palsy, dysphasia and dysarthria. He also revealed a blepharoptosis of the right eyelid, impairment of abduction on left side. He appeared hypersomnic, exhibited a reversed sleep–wake cycle, and was disoriented in space and time. It was also noticed that, he also had a personality change. Cerebral Magnetic Resonance Imaging (MRI) showed a bilateral thalamic stroke with extension to the right midbrain, temporal and occipital lobes. This unique case represents a highly uncommon variant of the “top of the basilar” syndrome because of a special anatomic arterial variation named Artery of Percheron (AOP).