Endoscopic third ventriculostomy limited by artery of Percheron.

The irrigation of the thalamus depends mainly on the thalamoperforating arteries. There are many anatomical variations in these arteries, the best known being the artery of Percheron. We report a case of a 13-year-old male presented with headache and decline in his mental status. Imaging features showed obstructive hydrocephalus secondary to a mass at the level of the mesencephalon so an endoscopic third ventriculostomy was performed. During the procedure a thalamoperforating artery was encountered at the level of the tuber cinereum limiting the perforation of the third ventricle floor. The present case emphasizes the importance of knowing the anatomy of these arteries and the identification of their main variants during neurosurgical procedures.