Encyclopedia of Neurological Disorders | Perineural Cysts

Definition

Perineural cysts (also called Tarlov cysts) are abnormal fluid-filled sacs located in the sacrum, the base of the spine.

Description

Perineural cysts appear to be dilated or ballooned areas of the sheaths that cover nerve roots exiting from the sacral area of the spine. The spaces or cysts created by the dilated sheaths are directly connected to the subarachnoid area of the spinal column, the area through which cerebrospinal fluid flows. Many people have perineural cysts but no symptoms at all; in fact, the majority of people with these cysts are completely unaware of their existence. However, when conditions cause these perineural cysts to fill with cerebrospinal fluid and expand in size, they can begin to compress important neighboring nerve fibers, resulting in a variety of symptoms, including pain, weakness, and abnormal...