Abstract Intradural arachnoid cysts are a rare cause of spinal cord compression. In symptomatic cases neuropathic pain, gait disturbance, and paraparesis or quadriparesis are often present. Postoperative arachnoid cysts have rarely been reported. We describe a 56-year-old male who developed progressively enlarging arachnoid cysts with cauda equina syndrome and vertebral body erosion after lumbar surgery. The clinical presentation of the patient, the possible mechanisms of cyst formation, and the management of the disease are discussed with regard to previous literature.