Posterior reversible encephalopathy syndrome mimicking a cerebral tumour.

Posterior reversible encephalopathy syndrome (PRES) is a syndrome characterised clinically by headache, confusion, seizures, vomiting and visual disturbances with radiographic vasogenic oedema. CT imaging is typically normal, non-specific or suggestive of PRES or stroke. MRI usually shows symmetrical parietal and occipital lobe vasogenic oedema. The authors discuss a 58-year-old man presenting with right homonymous haemianopia, hypertension and ataxia. CT imaging suggested a left occipital lobe space occupying lesion (SOL). Surprisingly, subsequent contrast enhanced MRI showed characteristic bilateral vasogenic oedema in occipital and temporal lobes indicative of PRES. Hypertension, an associated predisposing factor, was present in this case and symptoms improved with antihypertensive therapy. This case highlights PRES may present with asymmetrical CT imaging findings mimicking a SOL. PRES is a potentially reversible condition with prompt treatment. MRI is essential in diagnosing both PRES and the cause of acute visual loss.