Gas-filled intradural cysts of the lumbar spine and the possible pathogenesis

Abstract 

Background context

There have only been four reports of gas-filled intradural cysts, and the pathogenesis is unknown.

Purpose

To document the radiologic and histopathologic features of gas-filled intradural cysts and to discuss the pathogenesis with a review of the literature.

Study design

Case report.

Methods

A 67-year-old woman, admitted to our institute, presented with severe right thigh pain. On admission to the institute, enhanced magnetic resonance imaging, showed a cystic lesion in the spinal canal at the L2–L3 level, with an intensity suggesting the presence of gas. An enhanced region around the cyst was noted. Computed tomography after discography also revealed a water-soluble contrast filled the subarachnoid space and area around the cyst, but not inside.

Results

The cyst was surgically resected. One of the nerve roots was firmly adherent to the gas-filled cyst. The cyst wall comprised fibrous tissue, including small granulations and herniated disc material.

Conclusion

Gas-filled intradural cysts are rare. The pathogenesis appears to involve gas in a degenerated intervertebral disc, and spontaneous absorption of herniated disc material.

Keywords: Gas-filled cyst, Vacuum phenomenon, Herniated disc absorption