Skip metastasis of intradural Ewing's sarcoma in the lumbar spine: illustrative case.

backgroundEwing's sarcoma in the intradural and extramedullary space is exceedingly rare. Here, the authors report a rare case of skip metastasis of intradural extramedullary Ewing's sarcoma in the lumbar spine. OBSERVATIONS: A 73-year-old man underwent surgery at another hospital for an intradural extramedullary spinal tumor at the L4 level, initially suspected to be a schwannoma. However, postoperative histopathological examination revealed Ewing's sarcoma; subsequently, he received local radiotherapy and chemotherapy. Thirty-eight months postoperatively, the patient developed severe low back pain and bilateral leg pain, accompanied by urinary retention and bowel dysfunction. MRI showed a new intradural extramedullary tumor at the L1 level. Gross-total resection was performed, and histopathological examination confirmed Ewing's sarcoma. Four months after the second surgery, MRI of the lumbar spine revealed tumor recurrence. The patient remained asymptomatic and was treated with additional radiotherapy and chemotherapy, resulting in significant tumor size reduction. LESSONS: This case highlights the aggressive nature of intradural extramedullary Ewing's sarcoma and its propensity for early recurrence and metastasis. Although this presentation is extremely rare, postoperative adjuvant radiotherapy and chemotherapy, including craniospinal irradiation, should be considered to reduce recurrence risk. Frequent follow-up imaging is essential for the early detection of metastatic disease. https://thejns.org/doi/10.3171/CASE25361.