Arachnoid cysts constitute 1% of all intracranial lesions. Localisation is most often in the mid cranial fossa and rarely in the posterior fossa. These cysts contain fluid that is biochemically consistent with cerebral spinal fluid. By creating pressure on surrounding tissues, posterior fossa arachnoid cysts can lead to clinical symptoms. However, diagnosis is generally delayed because of the non-specific nature of the complaints, such as ataxia, headache and dizziness. The case is here reported of a patient who presented with complaints of general fatigue and a headache that had been ongoing for more than 1 year, accompanied by nausea for the last 2 months, and during the followup for etiology of iron deficiency anaemia, a giant arachnoid cyst was determi
