Complete loop of the posterior cerebral artery with ruptured aneurysm at the origin of the medial posterior choroidal artery. A case report

BACKGROUND: Anatomical anomalies of the PCA are unusual and their association with an aneurysm is exceptional. A unique case of a complete loop of the posterior cerebral artery associated with a ruptured aneurysm is presented. CASE DESCRIPTION: A 69-year-old woman with a subarachnoid hemorrhage in World Federation of Neurosurgical Societies grade IV was diagnosed with a loop of the right PCA with an aneurysm at the apex of the loop. At surgery, the aneurysm was found to arise at the origin of the MPChA and it was clipped. Three months later, after improving to Glasgow Outcome Scale 3, the patient died of unrelated cause. CONCLUSIONS: To our knowledge, a complete loop of the PCA associated with an aneurysm at the origin of the MPChA has never been described. Microneurosurgical approach via subtemporal craniotomy was safe and effective in displaying the anomalous anatomy and allowing perfect clipping of the aneurysm.