A Case of Spontaneous Regression of Lumbar Synovial Cyst and Literature Review

ABSTRACT

There have been many reports about lumbar synovial cysts, discussing surgical or interventional treatment methods. However, there have been few reports about spontaneous regression of the cyst. We report a case of a lumbar synovial cyst that regressed spontaneously. To the best of our knowledge, this is the first report of a spontaneously regressed lumbar synovial cyst in Korea. The patient was a 59-year-old man who presented with a 6-month history of insidious pain onset in the lower back and right buttock. Upon MRI of the lumbar spine, grade 1 spondylolisthesis was revealed at the L4-5 level. An about 6mm-sized extradural cyst was detected at the medial side of the right L4-5 facet joint. His symptoms were disappeared upon facet block with 0.5% bupivacaine bilaterally at the L4-5 level. Six years later, he revisited our clinic due to low back pain and left leg radiating pain. Upon lumbar MRI, aggravated L4-5 spondylolisthesis with left-side disc protrusion was observed. However, we could not find the synovial cyst around the right L4-5 facet joint that had existed 6 years prior. The patient was treated conservatively because he refused surgery.