I had an MRI to find out what's causing my severe back and leg pain. The MRI showed a definite problem they thought was a tumor. I was scared to death. It turned out to be a synovial cyst. Did the doctors miss something on the MRI?

Usually a synovial cyst of this type looks like a separate structure with clear margins. It's located outside or next to a facet joint in the spine. The cyst is filled with a clear fluid.

The MRI has a hard time telling the difference between fluid in the spinal column, joint fluid, or hemorrhage. An abnormal signal may be all that's recorded for tumors, cysts, or other soft tissue masses.

The doctors rely on the patient's history, symptoms, clinical exam, and the imaging studies to make a diagnosis. The final diagnosis is made during the operation when the mass is clearly identified or removed and sent to pathology.