Ruptured aneurysm originating from an aberrant medullary branch of the proximal posterior inferior cerebellar artery: case report.

OBJECTIVE: Aneurysms that arise from a small branch of the posterior inferior cerebellar artery (PICA) are very rare. All reported PICA branch aneurysms originated from the choroidal branches or PICA communicating branches. No aneurysms of the PICA medullary branch have been reported previously.

CLINICAL PRESENTATION: A 62-year-old woman presented with a subarachnoid hemorrhage and intraventricular hemorrhage. Angiography showed a globular-shaped aneurysm arising from an aberrant branch of the anterior medullary segment of the left PICA. At the time of operation, the arterial branch was found to send some perforators into to the medulla oblongata and cervical spinal cord.

INTERVENTION: Aneurysm trapping was performed. Postoperatively, the patient had a mild transient difficulty in swallowing that may have been caused by manipulation of the vagus nerve rootlets.

CONCLUSION: Aneurysms can develop from a proximal medullary branch of the PICA and lead to subarachnoid hemorrhage and intraventricular hemorrhage. Trapping can be judiciously attempted to treat this precarious aneurysm.