Endovascular Therapy for an Aneurysm of a Distal Posterior Inferior Cerebellar Artery via the Ipsilateral Persistent Primitive Proatlantal Artery: A Case Report

OBJECTIVE: We describe the rare case of a patient who was treated for a ruptured distal posterior inferior cerebellar artery (PICA) aneurysm via an ipsilateral persistent primitive proatlantal artery (PPPA). CASE PRESENTATION: An 86-year-old female with a medical history of hypertension presented with headache and nausea. CT showed subarachnoid hemorrhage in the posterior cranial fossa, and CTA revealed an aneurysm at the left-side distal PICA. In the left-sided common carotid angiography, the artery with a branch of the occipital artery from the external carotid artery was described. This artery continued as the V3 segment and entered the dura via the foramen magnum. The artery perfused the territory of the left vertebral artery and PICA. We concluded that the artery, which entered the dura, was a PPPA. We decided to perform endovascular therapy that passed through the PPPA. The aneurysm was located in the cortical segments, beyond the cranial loop. We decided that parent artery occlusion (PAO) would be more effective than selective coil embolization to achieve safe and adequate hemostasis. The patient had a good outcome with PAO not assessing collateral circulation. CONCLUSION: The emergency endovascular treatment with rare vascular variations requires accurate anatomical knowledge for treatment.