Fatal traumatic aneurysm of the posterior inferior cerebellar artery with delayed rupture.

Traumatic aneurysms of intracranial arteries are rare, forming less than 1% of all intracranial arteries. They may be associated with penetrating and non-penetrating trauma. Most cases are associated with fracturing of the skull. Rupture of traumatic aneurysms occur in up to 50% of cases and are typically delayed from days to weeks following the initiating trauma. We report a case of a 22-year-old man who was punched to the head. He was rendered unconscious but recovered and had a GCS of 14 on admission. CT scans showed subarachnoid hemorrhage. An initial angiogram was negative but on day 7 following the incident he was noted to have a 1 mm aneurysm of the posterior inferior cerebellar artery on CT angiogram. On day 9 he collapsed and was found to have new subarachnoid hemorrhage and to have a 4.0 mm × 3.7 mm. He did not recover and was declared brain dead on day 12. At autopsy, there was a 4.0 mm aneurysm of the left PICA just after the origin of the artery. Histological examination confirmed the presence of a traumatic false aneurysm in the left PICA. This case study shows sequential radiological imaging with pathologiocal correlation.