We herein describe the case of a focal spontaneous spinal epidural abscess who was initially diagnosed to have a free fragment of a lumbar disc. A 71-year-old woman presented with history of low back and right leg pain. Magnetic resonance imaging suggested a peripherally enhancing free fragment extending down from S1 nerve root axilla. Preoperative laboratory investigation showed elevation of c-reactive protein (CRP), erythrocyte sedimentation rate (ESR) levels. She was taken for surgery and a fluctuating mass at the axilla of S1 nerve was found. When the mass was probed with a dissector, a dark yellow, thick pus drained out. Pus cultures were negative. Patients who present with extreme low back plus leg pain and increased leucocyte count, ESR and CRP levels should raise the suspicion of an infection of a vertebral body or spinal epidural space.