Distal anterior choroidal artery aneurysm following iatrogenic posterior cerebral artery occlusion : a case report and review of literature.

Aneurysms of the anterior choroidal artery are uncommon and account for only 2-5% of all intracranial aneurysms. Distal anterior choroidal artery aneurysms are rare and the pathogenesis of this aneurysm may be different from typical proximal ones. We describe an unusual case of ruptured de novo distal anterior choroidal artery aneurysm in a 55 year-old man who had previously undergone endovascular proximal occlusion for a fusiform aneurysm of the ipsilateral posterior cerebral artery (PCA). A comprehensive review of literature using Medline, PubMed and all related journals was also performed. Only 34 reported distal AchoA aneurysms were found: 16 associated with moyamoya disease, 10 idiopathic, two with atherosclerosis, two with arteriovenous malformation, two dissecting, one infectious and one due to trauma. It is probable that the increased hemodynamic stress within the AchoA contributed to the formation and rupture of the reported aneurysm. This late complication needs to be considered when large intracranial vessels are iatrogenically occluded in the management of complex intracranial aneurysms.