Spinal extradural meningeal cysts are uncommon and rarely cause neural compression. The clinical, radiological, and histopathological characteristics of the lesions are discussed and previous reports reviewed.
The authors describe five cases of a spinal extradural meningeal cyst (three female and two male patients, with a mean age of 47 years (range 14–75 years). Four of the cysts were located at the thoracolumbar level, the fifth at the sacral level. Radiological and neuroimaging-based diagnosis was made using a combination of magnetic resonance imaging, myelography, and/or computerized tomography (CT) myelography.
A connection between the spinal subarachnoid space and the cyst cavity was demonstrated on myelography and/or CT myelography in all cases, and dural defects were confirmed visually intraoperatively. In all cases histopathological examination confirmed that the cyst wall was formed by nonspecific fibrous connective tissue without a single-cell layer of inner arachnoid lining.
A diagnosis of spinal extradural meningeal cyst is difficult to make based solely on histopathological examination. It is essential that the final characterization and diagnosis be based on intraoperative inspection combined with radiological and histopathological findings.