Case Report of De novo cavernous carotid artery aneurysm following an acute stroke intervention for a carotid occlusion.

and Importance: Arterial dissections are a common cause of stroke in young patients but may occur at any age. There is no previous reports of an intracranial carotid artery dissection that evolved spontaneously into both complications, i.e. stroke and pseudoaneurysm. To our knowledge this is the first case of arterial dissection complicated by an occlusion and a pseudoaneurysm occurring at the same site.The patient is a 57 years old female was found by a family member with complete right-side weakness and without the ability to communicate. On admission her NIHSS was 18 and her cerebral angiogram showed a left cavernous carotid occlusion. Mechanical thrombectomy failed to open the occlusion therefore an enterprise stent was deployed. Four weeks after the left ICA stent placement, the patient presents with a complete ptosis of the L eye with minimally reactive pupil, a third nerve palsy, CTA showed an 8 mm aneurysm of the L cavernous ICA. A cerebral angiogram was performed and showed a 10 x7 mm cavernous pseudoaneurysm. The decision was made to treat the aneurysm with pipeline assisted coiling. The procedure went well without any complications.Intracranial dissection/occlusion is a frequent cause of brain infarction especially in young patients. Clinical signs of subarachnoid hemorrhage, compressive nerve palsies and epistaxis in a patient who had endovascular treatment for an intracranial arterial dissection occlusion should be considered as signs for pseudoaneurysm formation and an angiography should be obtained as soon as possible.