Patient went on to a laminectomy. 

Histology

MICROSCOPIC DESCRIPTION:

1. The sections include ligamentum flavum, connective tissue and lamellar bone. A cyst is present, which is lined by synovial cells and some multinucleated giant cells. The lumen contains fibrinoid material. There is no increased acute inflammation. No granulomas are seen. There is no evidence of malignancy. The features are those of a synovial cyst.

2. The sections contain ligamentum flavum, connective tissue and lamellar bone. No cyst or tumor is seen.

DIAGNOSIS:

1. Dural mass: synovial cyst.
2. Extradural tissue: no significant abnormality seen.

Discussion

It is important not to forget synovial cysts as a cause of peripherally enhancing masses in the extrathecal space, anywhere along the spinal canal, but particularly in the lower lumbar and midcervical regions.