Synovial cyst of the thoracic spine causing myelopathy

Pre- and postoperative follow-up of a patient with progressive myelopathy caused by a thoracic synovial cyst developing within 6 months.

To present the natural history of a developing thoracic synovial cyst and to highlight this unusual case.

Thoracic synovial cysts are a rare finding and can produce myelopathy from spinal cord compression. The patient presented with progressing spasticity and sensory loss of both legs. Hereditary motor-sensory neuropathy was suspected and excluded by a molecular genetic examination. The cause of deterioration was finally found in an MRI of the thoracic spine revealing the rapid growth of a synovial cyst that had been detected in a previously performed MRI 6 months earlier.

Clinical and MRI details are presented documenting the natural history and development of a thoracic synovial cyst causing myelopathy.

The thoracic synovial cyst was successfully decompressed. Stabilization and fusion were not performed. The myelopathy resolved after surgery and the patient stays well in the 6-months follow-up.

Although thoracic synovial cysts are a rare finding, they have to be considered as a source for progressive myelopathy. If an MRI of the spine does not reveal any pathologies, it should be repeated even after a short period of time if the patient's condition deteriorates, continuously to detect newly developed findings.