Synovial or ganglion cysts usually present in the joints of the extremities13)
. Spinal synovial cyst can be defined as a soft tissue mass located extradurally along the medial border of a degenerated facet joint, especially L4-5 level1,4,8,11,12)
. These cysts are filled with clear or xanthochromic fluid and have a synovial-like epithelial lining with a demonstrable connection to a joint capsule3,11)
. If the synovial cell lining and the communication with a joint capsule are absent, the cyst is classified as ganglion11)
Intraspinal synovial cysts are rare but have been documented with increasing frequency because of the improvement of neuroradiological imagings4)
. An MRI is considered a good modality for diagnosis. On MRI, cysts appear as well-circumscribed, epidural mass lesions that are hypo- and hyper-intense on T1 and T2 weighted images, respectfully. Bleeding into a synovial cyst may cause a sudden expansion of the cyst leading to compression of the epidural space result in root compression symptoms. Hemorrhage into a synovial cyst results in an acute increase in pain and radicular symptoms, including neurological deficits12)
. Hemorrhagic presentation can be caused by anticoagulation treatment, trauma, disc herniation, vascular anomaly, and neoangiogenesis in the cyst4)
. In addition, high vascularization of the cyst can cause hemorrhage in spite of minor trauma or just spinal instability. Synovial cyst hemorrhagic events in some cases can occur despite the absence of trauma or coagulopathy13)
. As a result, other yet to be determined risk factors for synovial cyst hemorrhage occurrence exist prompting the need for more studies.
The treatments for synovial cysts either involve conservative modalities or surgical treatment. Non-hemorrhagic synovial cysts are occasionally treated by percutaneous aspiration with successful resolution of symptom6)
. The injection of corticosteroid agents into the facet joint may be an treatment option. Despite conservative treatment, recurrence of cyst with symptoms is frequently occurs6)
. The natural history of spinal synovial cysts is unknown, but spontaneous remissions of a synovial cyst on follow up imaging with improved symptoms have been reported5)
. Surgical excision with decompression is the primary treatment for lumbar hemorrhagic synovial cysts. Few cases with acute symptoms require emergency surgery. However, pain can be treated with steroid injections and bed rest in substantial number of patients. Immediate diagnosis and appropriate surgical excision can produce good outcome4,7,11,12)
We report of a case in which hemorrhage into a right L2-3 facet synovial cyst causing an acute back pain and radiculopathy. Treatment by resection of the cyst and evacuation of the hematoma led to complete neurological recovery.