Middle Fossa and Sylvian Fissure Arachnoid Cysts Associated With Intracystic Hemorrhage and Subdural Hematoma

Abstract

Introduction: Arachnoid cysts are relatively common intracranial mass lesions that occur most often in the middle cranial fossa; however, many are asymptomatic. Intracystic or subdural hematoma and hydromas are related to the rupture of a Sylvian fissure arachnoid cyst either incidentally or due to head trauma. We report 9 cases of middle fossa and sylvian fissure arachnoid cysts associated with intracystic hemorrhage and subdural hematoma in 2 cases. Patients and Methods: In our retrospective study, 9 of 20 patients with intracranial arachnoid cysts had middle fossa and Sylvian fissure arachnoid cysts. We analyzed their demographic characteristics and the chief compliant as well as the Galassi classification of arachnoid cysts and their association with subdural hematoma. Results: The male to female ratio was 2:1 and the mean age of our patients was 14.6 years (7 mo to 29 y). The left side was affected more than the right (5:4). The most common symptom was headache (two thirds of patients), followed by seizure in 2 cases and macrocephalus in 1 case. According to the Galassi classification, type I cysts constituted 55% of patients, type II presented in 1 case, and type III in one third of the cases. Subdural hematoma occurred in 2 of our patients who were operated. Conclusions: The annual hemorrhage risk for patients with middle cranial fossa cysts remains very low. However, when hemorrhage occurs, in most occasions it can be effectively managed only by hematoma evacuation; however, occasionally microsurgical and endoscopic cyst-wall fenestration to basal cisterns and, rarely, cystoperitoneal shunt might be needed.