Intracranial arachnoid cyst (review of 20 cases)

Introduction: The purpose of this study is to evaluate the distribution, clinical features, and treatment modalities of arachnoid cyst in our department. The study was carried out between April 1, 1996 and October 1, 2006 at the neurosurgery department, Ghaem hospital, Mashhad university of medical sciences. Material and Methods: Twenty patients with arachnoid cyst underwent surgery between April 1, 1996 until October 1, 2006, consisting of 12 males and 8 females ranging in age 5 to 68 years (mean age 32.4 years). Twelve patients underwent surgery and one patient underwent endoscopic fenestration, and cystoperitoneal shunting (medium pressure) was performed in 7 patients. All patients were followed for minimum of 6 months after surgery. Results: During the study period, 20 patients were investigated. The cysts had strong predilection for the middle cranial fossa in 12 patients (60%), suprasellar region in 1 patient (5%), the cerebral convexity in 1 patient (5%), posterior cranial fossa in 2 patients (10%), cerebellopontine angle in 3 patients (15%), quadrigeminal cisterns in 1 patient (5%). All of 20 cysts had clearly unilateral distribution, 12 (60%) were located on the left side and 8 (40%) on the right side. The most common symptoms on presentation were epileptic seizures (46%), increased intracranial pressure (34%), visual impairment (5%), headache (10%), cerebellar sign (5%). Conclusion: Arachnoid cysts have a strong predilection for the middle cranial fossa that may be explained by a meningeal maldevelopment theory. We also conclude that the major indication for surgery in patients with arachnoid cyst is the presence of intractable seizures, increased intracranial pressure, and compression of neuronal tissues. Headache only is not a surgical indication.