Iatrogenic Epidermoid Cyst of the Cauda Equina: A Late Complication of Lumbar Disc Herniation Surgery.

Abstract

Epidermoid cysts (ECs) account for 0.5% to 1% of all spinal tumors. They can be congenital or acquired. Acquired spinal ECs are extremely rare and are mostly caused by trauma, or secondary to iatrogenic procedure such as lumbar punctures or surgery for spina bifida. As far as we know, this is the first report of a spinal EC complicating surgery for a lumbar disc herniation. A 69-year-old woman, with a history of L3-L4 lumbar disc herniation surgery 30 years earlier, presented because of low back pain, weakness of her lower limbs, and bladder dysfunction evolving for 2 years. Magnetic resonance imaging identified an intradural cystic lesion extending from the medullary cone to the L4 level, evoking an EC. The diagnosis was confirmed peroperatively. Neurologic motor signs improved postoperatively but not the sphincter disorders. Despite the extreme rarity of this event, we should be aware of the potential de novo development of epidermoid tumors in patients who undergo surgery for lumbar disc herniation. Concerns must be given to persistent low back pain and delayed neurologic symptoms in these patients.