Traumatic intracranial aneurysm in a distal posterior cerebral artery: A case report and literature review.

Background: Traumatic intracranial aneurysms (TICAs) are rare and known to rupture easily and have a high mortality rate. Case Description: An 87-year-old male patient with no neurological deficits presented to our hospital after head trauma. Computed tomography (CT) revealed a tentorial acute subdural hematoma (ASDH). The patient was managed conservatively and discharged home six days after hospitalization. Two days later, the patient returned with a severe headache. CT showed that the ASDH had enlarged and extended from the tentorium to the convexity. CT angiography and digital subtraction angiography revealed a pseudoaneurysm in a branch of the left posterior inferior temporal artery. The patient was diagnosed with an enlarged ASDH due to a ruptured TICA that arose from the P3 segment. We performed endovascular intervention with parent artery occlusion (PAO) using n-butyl-2-cyanoacrylate (NBCA). The parent artery was accessed through the left posterior communicating artery because left vertebral angiography revealed an aplastic left P1 segment. After navigating the microcatheter near the aneurysm, we injected 33% NBCA into the parent artery. The pseudoaneurysm disappeared after injection. The patient was discharged on hospital day 25 despite persistent delirium. Conclusion: This is the first report of a TICA arising from the P3 segment that was treated with PAO using NBCA. TICAs are rare; however, a TICA must be considered when an enlarged hematoma caused by head injury is detected.