title: Posterior communicating artery aneurysm presenting with haemorrhage into an arachnoid cyst.
abstract: A patient is reported on with a subarachnoid haemorrhage (SAH) from an aneurysm of the posterior communicating artery, who initially presented with a sentinel bleed into an arachnoid cyst and normal magnetic resonance angiography (MRA) of the intracranial vasculature which led to a delay in diagnosis. Although this is a very rare presentation of a relatively common condition, it is important to recognise the importance of intracystic haemorrhage in such circumstances as well as the limitations of MRA, as a delay in diagnosis may have serious clinical consequences.
authors.affiliation: National Hospital for Neurology and Neurosurgery, London, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Barker
authors.forename: R R
authors.initials: RR
authors.lastname: Phillips
authors.forename: I F
authors.initials: IF
authors.lastname: Moseley
authors.forename: W J
authors.initials: WJ
authors.lastname: Taylor
authors.forename: N D
authors.initials: ND
authors.lastname: Kitchen
authors.forename: J W
authors.initials: JW
authors.lastname: Scadding
mesh_terms: D000328:Adult; D016080:Arachnoid Cysts / Q000150:complications*; D002533:Cerebral Angiography; D002536:Cerebral Arteries; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications*; D018810:Magnetic Resonance Angiography; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000175:diagnosis* / Q000209:etiology*; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis* / Q000209:etiology*; D014057:Tomography, X-Ray Computed