Case of Recurrent Artery of Heubner Aneurysm Masquerading as Partially Thrombosed A1 Aneurysm Radiologically.

Recurrent artery of Heubner (RAH) aneurysms are rare, with only 7 reported cases in the literature to date. In evaluating cerebral aneurysms, cerebral digital subtraction angiogram (DSA) is considered the gold standard and demonstrated the RAH aneurysms in previous case reports. We present a case of spontaneous subarachnoid hemorrhage secondary to RAH aneurysmal rupture, with initial DSA misleading, suggesting minor aneurysmal filling of a presumed thrombosed A1 segment aneurysm instead.A 71-year-old female presented with sudden-onset severe headache, nausea, and vomiting. Computed tomography along with computed tomography angiogram revealed a left-sided subarachnoid hemorrhage and a 5-mm aneurysm arising from either the left A1 or distal internal carotid artery. In addition, complex anterior cerebral artery anatomy with trifurcation was noted. This along with partial aneurysmal thrombosis made identification of the anatomy difficult on subsequent DSA, though a residual neck was still suggested to be arising from A1. Intraoperatively, the aneurysm was found to be arising from the RAH instead and was successfully secured by clipping.This case highlights the risk of RAH aneurysms masquerading as emanating from the A1 segment on DSA. Case particularities of complex anatomy and aneurysmal thrombosis were contributory. Other factors such as severe vasospasm, microaneurysms, and aneurysmal compression by overlying hematoma or brain parenchymal swelling could also distort DSA interpretation. These are important considerations in treatment planning by neurovascular surgeons and endovascular neuroradiologists.