Intraspinal synovial cysts: natural history and diagnosis by CT

Synovial cysts rarely have been recognized in the spinal canal. In one subsequently proved case, and in three other unproved cases that we are reporting, computed tomography (CT) showed the synovial cyst as an encapsulated cystic structure that was adjacent to a degenerated L4-5 facet joint. Although a synovial cyst may clinically simulate a herniated disk or a intraspinal tumor at myelography, it can be identified reliably by CT, and thereby exploratory laminectomy may be prevented