Late detection of supraclinoid carotid artery aneurysm after traumatic subarachnoid hemorrhage and occlusion of the ipsilateral cervical internal carotid artery

We report the first case of traumatic aneurysm of the supraclinoid internal carotid artery (ICA), which we speculate may have developed or grown after traumatic occlusion of the ipsilateral cervical ICA. A 26-year-old man presented with severe traumatic subarachnoid hemorrhage (SAH) and occlusion of the right cervical ICA after a motor vehicle accident. Three-dimensional CT angiography on admission showed no aneurysm. However, cerebral angiography 3 weeks after the injury showed a large aneurysm of the right supraclinoid ICA. The aneurysm was trapped, and pathological examination showed that it was a traumatic aneurysm. In this case we cannot be sure that the aneurysm was not present on admission. In view of the significant SAH, a lesson of this case may be to suspect such an aneurysm early on and perform early diagnostic cerebral angiography.