A Caucasian female previously diagnosed with anorexia nervosa was referred by psychiatric services to the general medical team. She presented with dehydration, vomiting, weakness, a body mass index of 13 kg/m2 and was treated with intravenous and enteral supplementation. During admission her vomiting worsened and she developed visual hallucinations and confabulation. Neurological examination demonstrated cerebellar signs and bilateral papilloedema on fundoscopy. Subsequent magnetic resonance imaging of the brain revealed a large fourth ventricular tumour causing obstructive hydrocephalus. The tumour was excised and histologically confirmed to be a choroid plexus papilloma. Postoperatively her neurological symptoms and negative feelings towards eating resolved.