Synovial cyst of the high cervical spine causing myelopathy.

The authors describe the myelographic and postmyelographic CT findings of an extradural mass with cord compression in an 82-year-old woman. Synovial cysts generally occur posterolaterally and are associated with degenerative facet joints; an unusual site together with facet joint disease should alert the observer to the possibility of a synovial cyst.