Clinical and magnetic resonance features of primary intracranial arachnoid cysts.

The clinical features of 33 patients with primary intracranial arachnoid cysts are reviewed. Magnetic resonance imaging was performed in 9 patients and was particularly useful in the multiplanar definition of complex cysts and in differentiating arachnoid cysts from other lesions that are hypodense on computed tomographic scans. Hydrocephalus, cranial nerve palsies, or symptomatic brain compression was considered an indication for surgical intervention in 21 patients. Outcome was uniformly good: mild focal weakness and seizure disorders constituted the sequelae.