Giant intracranial epidermoid cyst and dementia

lntracranial epidermoid cysts rarely present with a progressive dementia and ataxia. A 67 year old lady is reported who had been suffering from generalised tonic clonic seizures over a 60 year period. She presented with a 12 month history of progressive mental deterioration which was treated conservatively without benefit. Recent appearance of progressive ataxia prompted further investigations and a giant epidermoid cyst in the left middle and anterior cranial fossae was discovered. Subtotal excision has resulted in clinical improvement. The dangers of "waiting and watching" are highlighted.