The patient is 55-year-old female, consulting her physician because of lumbago as the chief complaint. She was hit by a motor vehicle at 12 years of age and suffered a severe impact on her back. She developed lumbago in July, 2003 and an MRI revealed the pathology of compressed thoracic spine anteriorly. The mass showed low intensity on T1WI and high intensity on T2WI from Th9 to L1 at the dorsal side. On admission she had difficulty with sensorimotor disturbances; interimittent claudication and impairment of sense of temperature and touch in the lower extremities. Surgical intervention was performed to reduce her symptoms; osteoplastic laminoplasty expanding Th11 to L1 and application of the dura synthesis (Th10) was done to close the dural defect and reduce her symptoms. The thoracic spinal extradural meningeal cyst is rare in that it took more than 40 years to develop from the onset. In this report we covered a rare case with spinal thoracic extradural meningeal cyst improving the symptom after surgery.