A 55-year-old male who complained of frequent back pain accompanied by increasing weakness in the lower extremities was admitted to our hospital's Neurosurgery Department. No additional disease was in his history. Magnetic resonance imaging of the thoracic area, anterior epidural space, and paravertebral area revealed an approximately 55 x 9 mm lymphoma pressuring the spinal cord from the anterior. It was fusiformed with a dural tail, hypointense on sagittal T1-weighted imaging series, and hypointense on sagittal T2-weighted imaging series compared with the spinal cord, showing contrast enhancement. After gadolinium application, an extra-axial mass lesion was detected. The lesion was surgically removed from the patient, whom we thought had meningioma on the basis of radiology. However, histopathology resulted in the diagnosis of diffuse large B-cell non-Hodgkin lymphoma.