POSTERIOR COMMUNICATING ARTERY ANEURYSM PRESENTING WITH HEMORRHAGE INTO AN ARACHNOID CYST

A patient is reported on with a subarachnoid haemorrhage (SAH) from an aneurysm of the posterior communicating artery, who initially present ed with a sentinel bleed into an arachnoid cyst and normal magnetic re sonance 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 importan ce of intracystic haemorrhage in such circumstances as well as the lim itations of MRA, as a delay in diagnosis may have serious clinical con sequences.