Rapid progression of spinal epidural lipomatosis after percutaneous endoscopic spine surgery mimicking disc herniation

INTRODUCTION: Spinal epidural lipomatosis (SEL) is well known but uncommon complication of endoscopic spine surgery. Here, we present a case of SEL that progressed focally and rapidly after endoscopic spinal surgery. PRESENTATION OF CASE: A 67-year-old man presented with back and Lt. leg radiating pain. MRI of the lumbar spine demonstrated severe foraminal stenosis at Lt. L4/5/S1. He underwent endoscopic posterior foraminotomy at Lt. L4/5/S1. After surgery, his leg pain disappeared. A month after surgery, the patient developed Lt. leg pain again. MR images showed focally progressed epidural fat posterior to the L5 body. After removal of lipomatosis via endoscopic posterior decompression at L3/4/5, his symptoms improved. DISCUSSION: Mostly, the epidural fat accumulates insidiously, and distributes widely across several levels. And the increased accumulation of fat is predominantly posterior and posterolateral within the spinal canal. As in this case, focally progressed SEL anterior to the dural sac is rare. And focally progressed SEL can be misdiagnosed for disc herniation. CONCLUSION: SEL should be recognized as a rare complication of endoscopic spine surgery.