Extradural Spinal Arachnoid Cyst
- Spinal arachnoid cysts are most often seen in the thoracic spine, intradural-extramedullary in location, and often dorsal to the cord.
- Extradural spinal arachnoid cysts are rare.
- Most are asymptomatic. Larger cysts sometimes can cause mass effect on the cord and adjacent structures resulting in back pain, and, rarely, radiculopathy and myelopathy.
- Key Diagnostic Features: Non-enhancing cystic appearing intradural extra-medullary lesion is seen. Rarely, such lesions can be seen in the extradural compartment.
- DDx: Neurenteric cyst, perineural root sleeve cyst
- Rx: Observation; if symptomatic, excision.
