Microcystic meningioma mimicking an arachnoid cyst

Microcystic meningioma is a particular morphopathological form of benign meningiomas, with different imaging characteristics compared to other forms of meningiomas. It is presented the case of an 80 year old woman with repeated head injuries, initially operated for a right fronto-temporo-parietal pericerebral fluid collection. After four years, the patient returned with headache, confusional status, somnolence, symptoms wich appeared after a new head injury. Cerebral CT scan revealed a hypodense lesion in the right sylvian fissure of 5.7/3.5 cm, without perilesional edema, which was interpreted as an arachnoid cyst. Intraoperative, a soft, gelatin-fibrous tumor mass was identified, partially adherent to the dura mater and the underlying cortex, which was completely resected. The morphopathological diagnosis was microcystic meningioma. It is discussed the imaging aspect of the presented case compared to the literature data regarding the microcystic meningiomas and the relationship between head traumas and the occurrence of meningiomas