Severe Recurrent Hemorrhage of an Oncogenic Vertebrobasilar Junction Aneurysm Following Stent-Assisted Coil Embolization in Metastatic Testicular Choriocarcinoma.

Oncogenic cerebral aneurysms (OCAs) are rare, catastrophic lesions typically arising from distal middle cerebral artery (MCA) branches. We present a case involving an atypical OCA at the vertebrobasilar (VB) junction secondary to metastatic mixed testicular cancer predominantly comprising choriocarcinoma, which resulted in fatal rebleeding despite initial stent-assisted coil embolization. A male in his 30s with metastatic choriocarcinoma and leptomeningeal carcinomatosis presented with ambiguous subarachnoid hemorrhage (SAH) on initial MRI. Subsequent CT angiography (CTA) identified an outpouching suspicious for an aneurysm at the VB junction communicating with bilateral VAs, without localized acute SAH. Stent-assisted coil embolization was performed. On postoperative day six, the patient suffered unexpected catastrophic rebleeding. Despite rescue efforts, angiography revealed no intracranial flow, consistent with brain death. Neurointerventionists should be aware that OCAs can manifest in atypical locations like the VB junction. Due to the high risk inherent in their pathophysiology, patients with metastatic choriocarcinoma involving the brain should undergo proactive intracranial vasculature screening.