Three Cases of True Posterior Communicating Artery Aneurysm Treated by Endovascular Therapy

True posterior communicating artery aneurysms are rare because they form aneurysms in the posterior communicating artery itself. The nature of true posterior communicating artery aneurysms differs from that of normal internal carotid artery‐posterior communicating artery bifurcation aneurysms. True posterior communicating artery aneurysms are often caused by hemodynamic stress and usually exhibit aggressive progression. Here, we describe three cases of true posterior communicating artery aneurysms treated with endovascular therapy, one of which presented with a grown unruptured aneurysm, whereas the remaining cases presented with subarachnoid hemorrhages requiring surgical intervention. Two cases were successfully occluded and showed favorable outcomes following stent‐assisted coil embolization. In contrast, Case 3 developed intraoperative thrombosis, which resulted in occlusion of the parent artery of the posterior communicating artery and the patient being transferred to another hospital with a modified Rankin scale score of 5. When performing endovascular surgery for true posterior communicating artery aneurysms, navigating a microcatheter into the aneurysm can be problematic. Although parent vessel occlusion may be the last resort for true posterior communicating artery aneurysms, careful consideration must be given to the suitability of this procedure for true posterior communicating arteries, which are often accompanied by fetal posterior communicating arteries.