Discal cyst is a very rare lesion that can result in refractory low back pain and leg radiating pain. Because they are so uncommon, their exact origin and pathophysiology are still unknown. A 31-year-old man visited our institute due to low back pain and severe left leg radiating pain. Magnetic resonance images [MRI] revealed spherically shaped extradural cystic lesion at L2-L3 level. Computed tomography [CT] discography demonstrated obvious communication between the intervertebral disc and the cyst. The patient underwent posterior decompression and excision of cyst. The symptoms were remarkably improved immediately after surgery.