"Relapsing-remitting" bilateral synovial cysts of the lumbar spine. A case report.

A case of bilateral synovial cysts is reported. They were shown by MRI first on one side and later, on the contralateral side, concomitantly with a reduction in the size of the cyst. Because spine instability was also present the most acceptable assumption is that there may be a contiguity between the articular facets and the cysts, thus enabling the filling and emptying of the cysts itself.