Middle cranial fossa arachnoid cysts complicated with subdural collections

Abstract

Intracranial arachnoid cysts are congenital collections of fluid that develop within the arachnoid membrane be cause of splitting or duplication of this structure. It corresponds to 1% of all non-traumatic intracranial mass lesions 1 . Arachnoid cysts most frequently occur in the middle cranial fossa, followed by the posterior fossa, convexity, and suprasellar region. Middle cranial fossa cysts are more often associated with subdural hematoma, subdural hygroma, and intracystic hemorrhage. Usually, the patients present with signs and symptoms of intracranial hypertension, mainly headache and vomiting 2 . We report two cases of arachnoid cysts associated with concurrent subdural collections, describing their clinical presentation, radiographic findings and neurosur gical management. CaSeS Case 1 A 15-year-old male patient presented with a 3-day history of headache and vomiting. He reported an episode of mild head trauma without loss of consciousness four days before the admission. There was no history of drugs, alcohol abuse or previous neurological illness. The Glasgow coma score was 14 (confused conversation). Pupil reactions were normal and there was no other abnormality in the neurologic examination. Computed tomography (CT) revealed an arachnoid cyst in the left middle cranial fossa (Fig 1A) and a low-density crescentic collection across the entire left hemispheric convexity, corresponding to a chronic subdural hematoma, with signs of acute hemorrhage (Fig 1B). The patient underwent surgical treatment with evacuation of the subdural hematoma and endoscopic fenestration of the cyst to obtain communication with the chiasmatic cistern. The recovery was uneventful and an eight months follow-up CT showed a residual non-hypertensive cyst. There was no evidence of any subdural collection.