BACKGROUND Gas-containing pseudocysts rarely cause of lumbar radiculopathy. This report describes successful treatment of a gas-containing pseudocyst using percutaneous transforaminal endoscopy. CASE SUMMARY A 48-year-old man presented with severe pain and numbness in his right leg, which worsened upon walking or weight bearing. Computed tomography and magnetic resonance imaging revealed a gas-containing cyst compressing the left L5 nerve root at the L4-5 level. The pseudocyst was successfully removed using a percutaneous transforaminal endoscopic discectomy. Vivid and clear endoscopic imaging of the pseudocysts was performed intraoperatively. The patient experienced immediate pain relief and was discharged one day after the operation. The patient returned to work. Moreover, numbness in the right leg returned to normal within 6 months. At the one-year follow-up, there was no symptoms recurrence. CONCLUSION Transforaminal endoscopy offers excellent surgical visualization and facilitates meticulous operative manipulation, making it a minimally invasive approach for treating gas-containing pseudocysts in the intervertebral foramen.