Sacral epidural noncommunicating arachnoid cyst. Case report and review of the literature.

The authors examine the natural history of a spinal epidural arachnoid cyst and present their experience with its treatment in a 25-year-old man who presented with progressive cauda equina syndrome. Neuroimaging revealed two neighboring sacral epidural cysts. The cysts were completely removed via a sacral S1-4 laminectomy; no communication with the subarachnoid space could be found. The patient's postoperative course was uneventful. He experienced progressive improvement and, finally, complete resolution of symptoms and no recurrence of the cyst. Nabors Type I sacral epidural arachnoid cysts are rare; in some cases their origins and the mechanism by which they cause deterioration in the patients' clinical condition are debatable. Findings in the present case support the idea that some of these cysts are noncommunicating but progressive in their clinical presentation. This lesion type is also known to occur intracranially. A brief review of the literature is provided.