Arachnoid cysts: case series and review of the literature.

OBJECT: Arachnoid cysts are commonly encountered fluid collections in the central nervous system. Recent advances in neuroimaging have translated into an increased detection of these cysts; that is, diagnoses can be made more frequently at earlier stages. Significant advances have also been made in the surgical management of these lesions. The authors report on a case series that illustrates the diverse forms of presentation and the treatment modalities commonly used for arachnoid cysts. METHODS: Between January 2002 and December 2006, 20 patients with arachnoid cysts underwent surgery performed by the senior author at The Johns Hopkins Hospital. Seventy percent of the cysts were supratentorial, 5% infratentorial, and 25% spinal. All diagnoses were confirmed on neuroimaging, surgery, and histological examination. Included in the study were 12 male (60%) and eight female (40%) patients, ranging in age from 2 weeks to 39 years (mean age 10.9 years) at the time of surgery. Symptoms at presentation included headache (41%), weakness (23%), seizure (14%), hydrocephalus (9%), scoliosis (4%), cognitive decline (4%), and visual loss (4%). Twenty-five percent of the cysts were sylvian, 20% intraventricular, and 20% suprasellar. Supratentorial cysts were treated endoscopically in 73% of patients and with open resection in the remaining 27%. Complications included spasticity, hemiparesis, cerebrospinal fluid leak, hydrocephalus, and subdural hygroma. On follow-up evaluation, 60% of patients had stable cysts and improved symptoms, 13% complete symptom resolution, and 13% stable symptoms. All patients with spinal cysts underwent laminectomies and fenestration, and one cystosubarachnoid (CS) shunt was placed. Cyst reaccumulation occurred in three patients; two patients required cystoperitoneal (CP) and CS shunts. No deaths occurred. CONCLUSIONS: Most arachnoid cysts are found incidentally and can be managed conservatively. Symptomatic patients are surgical candidates. Treatments include CP shunt placement, craniotomy, or endoscopic fenestration, and stereotactic aspiration. Recent advances in neurosurgical techniques and neuroendoscopy continue to favor fenestration over shunt insertion as the method of choice for initial cyst decompression.