Primary extraskeletal Ewing's sarcoma of the lumbar nerve root: A case report

Ewing's sarcoma (ES) is a highly aggressive bone malignancy. Extraskeletal ES (EES) originating in the spinal canal is extremely rare. Herein, we report on a rare case of EES with a primary lumbar spinal nerve root including the complete diagnosis and treatment.

A young female patient presented with a complaint of right lower limb pain for 1 mo. Magnetic resonance imaging (MRI) revealed an 11 mm × 14 mm × 31 mm mass in the lumbar epidural region extending at the fifth lumbar spine (L5) level toward the right L5 neural foramen. Our initial diagnosis was an epidural schwannoma. The patient underwent total laminectomy, tumor resection and pedicle screw internal fixation and the L5 root tumor was found to have been completely removed intraoperatively. Histopathological examination of the lesion showed a typical ES with a large number of small, round cells. Immunohistochemistry analysis indicated positive CD99 and S100. After surgery, the patient received chemotherapy and radiotherapy with a 1 year of follow-up and no recurrent tumors or new lesions were found upon spine MRI and positron emission tomography/computed tomography reexamination.

Clinically, ES outside the bone should be considered when nerve root tumors are encountered inside and outside the spinal canal and the diagnosis should be determined by pathological biopsy. After surgical resection, chemotherapy and radiotherapy should be performed. After treatment, active follow-up and regular review should be completed.