A previously well 13-year-old girl presented with a 4-month history of progressively worsening headache and visual disturbance. At fourth presentation, examination showed bilateral papilloedema and a left homonymous hemianopia. CT and MRI scans revealed a tumour obstructing the third ventricle with consequent hydrocephalus. Following uncomplicated endoscopic surgery, both headache and visual function improved. Several features of the history were highly suggestive of raised intracranial pressure and were overlooked initially.