Pedunculated basilar terminus aneurysm with pseudo-septation due to anterior herniation through a perforated membrane of Liliequist.
Septations within cerebral arteries or aneurysms are exceedingly rare in the absence of associated fenestrations. We report an unusual unruptured pedunculated basilar apex aneurysm, with a "pseudoseptation" between the main aneurysmal sac and an anterior compartment, which was, in fact, represented by a perforation in the membrane of Liliequist, permitting anterior aneurysmal herniation into the carotid-chiasmatic cistern. The patient was successfully treated with detachable coils. This case is unusual on 2 accounts: 1) the aneurysm's appearance, and 2) the presence of a large fenestration in the membrane of Liliequist, of which anatomic features are herein reviewed.
Hacein-Bey
L
L
Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA. lhaceinbey@yahoo.com
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D000328:Adult; D001099:Arachnoid / Q000000981:diagnostic imaging* / Q000293:injuries*; D004677:Encephalocele / Q000150:complications* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000209:etiology*; D011859:Radiography; D012421:Rupture / Q000150:complications / Q000000981:diagnostic imaging