Subarachnoid Hemorrhage From Ruptured Pseudoaneurysm Secondary to Dissection of the Anterior Cerebral Artery: A Case Report.

Arterial dissections occur when blood enters and separates the layers of the arterial wall. They are typically classified as either subintimal dissections, which are associated with ischemia or infarction, or subadventitial dissections, which can lead to subarachnoid hemorrhage (SAH). Dissections most commonly occur extradurally, particularly in the extracranial segments of the carotid and vertebral arteries. When intradural, they tend to involve the distal vertebral arteries and the supraclinoid internal carotid artery (ICA). Less commonly, dissections affect the anterior cerebral artery (ACA) and middle cerebral artery (MCA). Treatment options include endovascular approaches such as coil embolization and flow diversion, as well as open cerebrovascular techniques, including parent vessel sacrifice and vessel trapping. However, due to the rarity of ACA dissections, particularly in the A1 segment, there are no established treatment guidelines. We present a rare case of an ACA-A1 segment dissection successfully treated with stent-assisted coil embolization, resulting in complete recovery.