2023 Volume 51 Issue 5 Pages 411-416
Dysplasia of the terminal portion of the internal carotid artery (C1) is rare in occurrence. Herein, we reported a case of dysplasia at the C1 portion of the internal carotid artery leading to the development, rupture, and subsequent expansion of an aneurysm due to the fragility of the twig-like vascular networks.
The patient was a 66-year-old man who presented with subarachnoid and cerebral hemorrhages along with acute hydrocephalus due to third ventricular obstruction. Cerebral angiography revealed splitting of the right internal carotid artery into two anomalous collateral vessels immediately after the bifurcation of the posterior communicating artery, forming twig-like vascular networks with an abnormal branch from the posterior communicating artery, which coursed through the middle cerebral artery. The aneurysm developed within these twig-like vascular networks.
Intraoperative findings revealed hypoplasia in the right C1 portion. The proximal portions of the right A1 and M1 portions were identifiable; however, after the bifurcation of the collateral vessels, they underwent transformation into cord-like structures, resulting in occlusion.
The aneurysm was enclosed within twig-like networks and was difficult to identify; therefore, neck clipping was performed using intraoperative cerebral angiography.
