Subarachnoid Hemorrhage Caused by Ruptured Posterior Inferior Cerebellar Artery Aneurysm Arising From the Extracranial Portion of an Anomalous Vertebral Artery

Abstract

Fig. 1 Three-dimensional computed tomography scan revealing a saccular aneurysm of the left posterior inferior cerebellar artery originating extracranially from the left vertebral artery (VA) located between the foramen magnum and the posterior C1 arch (arrow), and the anomalous course of the left VA (arrowhead). 499 CASE REPORT AbstractA 42-year-old woman presented with subarachnoid hemorrhage caused by a ruptured posterior inferior cerebellar artery aneurysm arising from the extracranial portion of an anomalous vertebral artery. We speculated that the aneurysm formed by dissection of the media because of its shape and location. Therefore, the aneurysm was isolated by trapping and excised, with occipital artery to posterior inferior cerebellar artery bypass. Histological examination showed a typical true aneurysm without evidence of dissection. This case suggests that an aneurysm of an anomalous artery is caused by hemodynamic stress and is a true aneurysm, not a dissection.

Intracranial Vertebral Artery Aneurysms: Clinical Features and Outcome of 190 Patients

“…VA aneurysms are reported to be located at the origin of the PICA (3,12), and aneurysms in the VAePICA junction comprised 63% of our cases. The origin and course of a PICA can be highly variable, with the aneurysm located even extracranially (8,20,31). The percentage of nonsaccular aneurysms was high-22%; in other series, 13%e41% (3,12,49).…”