Primary epidural extraosseous Ewing sarcoma of the spine in a 19-year-old male: illustrative case.

BACKGROUND: Primary epidural extraosseous Ewing sarcoma (EES) is a rare form of spinal Ewing sarcoma with soft tissue invasion of the spinal canal and neural foramen, without involvement of the bony spinal column. OBSERVATIONS: The authors report the case of a 19-year-old male presenting to the hospital with a 1-month history of left leg dysesthesias and neuropathic pain, followed by acute left leg weakness evolving over 1-2 weeks. Imaging revealed an epidural lesion at L2 with extension into the left L2-3 neural foramen. The patient underwent urgent surgery given the evolving neurological deficits. Pathological analysis revealed Ewing sarcoma. He subsequently underwent chemotherapy and radiation therapy. At the 6-week follow-up, he had improvement in left leg strength without any evidence of tumor residual on imaging. A systematic review identified 80 cases of primary epidural EES. The mean age at presentation was 21.2 years, with 81.3% of patients < 30 years of age. Most patients were initially treated with surgery (86.2%), followed by adjuvant radiotherapy and chemotherapy (77.9%). Survival and progression-free survival at 1 year were 81.1% and 75.0%, respectively. LESSONS: Given the rarity of primary epidural EES, defining common treatment strategies and prognostic markers is essential to guide clinical decision-making and patient counselling. https://thejns.org/doi/10.3171/CASE2635.