traumatic intracranial pseudoaneurysm is a rare condition , accounting for less than 1% of all aneurysms.7 ) of these , post - traumatic vertebral artery pseudoaneurysm is not well known , because the incidence of isolated trauma to the vertebral artery is extremely low . majidi et al.4 ) reported that incidence of vertebral artery dissection was 0.01% of patients with head and neck trauma . traumatic pseudoaneurysm ruptures are associated with a high mortality rate , because of high risk of rebleeding or regrowth . we report on a rare case of post - traumatic pseudoaneurysm arising from the right v4 segment of the vertebral artery . a 9-year - old child was admitted to the emergency room after a pedestrian car accident . on admission , motor power of all extremities showed a good grade but movement showed abnormal flexion in response to painful stimuli . brain computed tomography ( ct ) showed subarachnoid hemorrhage ( sah ) with intraventricular hemorrhage ( ivh ) , multiple facial bones , and temporal bone fracture ( figure 1 ) . external ventricular drainage and suboccipital craniectomy were performed for acute hydrocephalus and decompression of posterior fossa swelling . follow - up ct demonstrated resolution of the hemorrhage and his clinical condition recovered to stupor mentality . on the 15th hospital day , the patient showed decreased mentality into semicoma and ct scan revealed the onset of a new 3rd , 4th ventricle hemorrhage and aggravation of hydrocephalus . ct angiography and digital subtraction angiography confirmed a pseudoaneurysm measuring approximately 15 mm in size arising from the right v4 segment of the vertebral artery , near the origin of the posterior inferior cerebellar artery ( pica ) ( figure 2 ) . the dominancy of the vertebral artery was even in size and blood flow to the right pica territory was supplied from the right anterior inferior cerebellar artery ( aica ) , meaning the aica - pica complex ( figure 3 ) . therefore , we decided to occlude the parent artery for complete obliteration of the pseudoaneurysm . final angiography confirmed complete obliteration of the pseudoaneurysm with preservation of the right aica - pica complex ( figure 4 ) . after endovascular treatment , the patient did not show worsening of neurological condition . despite receiving intensive neurosurgical care , he died of acute respiratory distress syndrome on the 52nd hospital day ( figure 5 ) . the mechanism is direct vessel injury from the foreign body or bony fragments due to skull fracture , or vascular torsion , stretching , and pressure against adjacent structures . the location of these pseudoaneurysms is varied , and they are commonly found in the anterior circulation . biffl et al.2 ) reported that vertebral artery injuries are presented in 0.5% of blunt cervical traumas . detection of traumatic pseudoaneurysms is still a clinical challenge due to its diverse presentation and lack of widely accepted diagnosis and management guidelines.5 ) clinical manifestation of vertebral pseudoaneurysm rupture could be a local neck mass , or neurologic symptoms related to posterior circulation due to microembolization . these pseudoaneurysms carry significant risk of embolic stroke and mortality , with cited figures of 13% , respectively.13 ) however , some pseudoaneurysms of the vertebral artery , like v3 or v4 segment , which proceeds from c1 to a junction with the contralateral vertebral artery , could present with intracranial hemorrhage . in general , deterioration of traumatic pseudoaneurysms may occur within several weeks after initial trauma . after the formation of a pseudoaneurysm , sudden onset of rebleeding could be associated with increased intracranial pressure or clot lysis . the pseudoaneurysms might be safely observed because spontaneous thrombosis could occur , but rebleeding could sometimes occur.6 ) therefore , early diagnosis and proper treatment of a pseudoaneurysm is also mandatory and highly important . intervention could also be an effective method for management of pseudoaneurysm , particularly posterior circulation with poor clinical grade . in the current case , the patient presented with post - traumatic sah and ivh , which was mistaken for simple traumatic sah , and there was no initial evaluation for vascular injury . formation of a pseudoaneurysm should be suspected in patients with trauma , if there is thick sah accompanying a basal skull fracture . the mechanism of traumatic brain injury is also an important consideration for development of pseudoaneurysm . on the 15th hospital day with deterioration of level of consciousness , angiography confirmed a rupture of a pseudoaneurysm arising from the right v4 segment of the vertebral artery . at the time of admission , there was no cervical spine injury that could affect dynamic injury to the vertebral artery . the child was pushed by a reversing school minivan with very low velocity immediately after leaving his car . then , he fell down and was run over by the right rear wheel . therefore , the exact mechanism of vascular injury is ambiguous ; however , considering angiographic findings , we thought that pseudoaneurysm formation was due to the rupture of a perforating artery by traction injury or dissection . the definite treatment of traumatic pseudoaneurysm is a destructive method , meaning parent artery occlusion . we could occlude the right vertebral artery just proximal to the aica origin , because there was no visualization on initial angiography and non - dominant vertebral artery compared with the contralateral side . we report an extremely rare case of traumatic pseudoaneurysm rebleeding arising from the intracranial vertebral artery . post - traumatic intracranial pseudoaneurysm should be considered in any patient who exhibits neurological deterioration after head trauma . therefore , brain ct angiography is mandatory for evaluation of vascular injuries in patients with traumatic sah and for achievement of a better outcome , especially in cases showing thick sah around the brain stem or sah with accompanying basal skull fractures .