Epidermoid Cyst of the Lumbar Spine After Lumbar Puncture: A Clinical, Radiographic, and Pathologic Correlation.

Background: Epidermoid cysts can rarely arise as a late complication of lumbar puncture. We describe a young man who had a remote history of a lumbar puncture and who was subsequently found to have a lumbar spinal epidermoid cyst on imaging, after presenting with lower extremity radicular pain. Case description: A 24-year-old man with a remote history of lumbar puncture presented with lower back pain and radicular leg pain which had been ongoing for over a year. Despite conservative management, the patient's symptoms progressed to worsening back pain and left L4 radiculopathy. Magnetic resonance imaging of the lumbar spine demonstrated a peripherally enhancing, intradural, extramedullary lesion at L4-5. Diffusion-weighted imaging revealed diffusion restriction within the lesion, characteristic of an epidermoid cyst. The patient underwent an L4-5 laminectomy for resection of the intradural tumor. The lesion was noted to contain pearly white granules consistent with the appearance of an epidermoid cyst. Histopathology confirmed the diagnosis. On follow-up examination, the patient demonstrated improvement of his back pain and resolution of radicular symptoms.

Conclusions: Lumbar spinal epidermoid cysts may be either congenital or secondary to an iatrogenic cause. This patient had a remote history of lumbar puncture during workup for meningitis as a child. As a complication of a lumbar puncture, the formation of an epidermoid cyst can occur and is thought to be the result of implanted cutaneous tissue. This case provides a comprehensive illustration of the clinical, radiographic, intraoperative, and pathologic findings consistent with an iatrogenic epidermoid cyst.