Variant of Persistent Primitive Trigeminal Artery Associated with Giant Internal Carotid Artery Pseudoaneurysm

We report a rare variation of the left persistent primitive trigeminal artery with direct anastomosis with the ipsilateral posterior cerebral artery in a 53-year-old women. She was sent to the hospital with visual deterioration and consciousness disturbance (Glasgow coma scale = E4V3M5). Marked hydrocephalus was found. An associated giant pseudoaneurysm was shown arising from the cisternal segment (C6) of the left internal carotid artery (ICA). She received a Hunterian ligation of the left ICA for treatment of the aneurysm in another hospital 5 years previously. The neurosurgeon thereafter removed and clipped the pseudoaneurysm to relieve its mass effect against the optic chiasm. She died of the complication of sepsis following extensive infarction of the territory of the left anterior cerebral artery (ACA) 6 weeks later. This case stresses the significance of careful initial full 4-vessel survey, balloon test occlusion with neurophysiologic monitoring before surgical ligation if fetal circulation is present, and alternative endovascular treatment of the pseudoaneurysm using the GDC (Guglielmi detachable coil) system. Keyword: Persistent primitive trigeminal artery; Anomalous posterior cerebral artery; Pseudoaneurysm; Hunterian ligation; Guglielmi detachable coil (GDC)