Histologic Features and Prognosis of Spinal Intradural Extramedullary Ewing Sarcoma: Case Report, Literature Review, and Analysis of Prognosis

Background: Ewing sarcoma is a malignant neoplasm that primarily involves extremity long bones, the pelvis, and soft tissues of children. The intradural extramedullary space is an uncommon location for Ewing sarcoma, and there is therefore a paucity of information regarding the features and natural history of this particular presentation. There is controversy regarding preoperative diagnosis, surgical management, and postoperative care, and there are no accepted standards. Methods: Herein we present a 61-year-old man with an L1-3 intradural extramedullary Ewing sarcoma who underwent gross total resection of the tumor via laminectomy. Pathologic analysis revealed a diagnosis of Ewing sarcoma based on the characteristic immunohistochemistry and the presence of EWSR1-FLI1 fusion transcript by reverse-transcription polymerase chain reaction. Results: There have been 28 cases of intradural extramedullary Ewing sarcoma reported in the literature. Out of 29 cases including the current case, 18 cases (62.1%) were men. The median and mean ages were 32 and 34.0 years, respectively, with a peak age group of 10–20 years. Twenty-two of 29 (72.4%) cases involved the lumbar spine, followed by the cervical spine (n = 7, 24.1%). Long-term prognosis was poor, with 1-, 2-, 3-, and 5-year progression-free survival rate of 75.0%, 56.3%, 37.5%, and 18.8%, respectively. The 1-, 2-, 3-, and 5-year overall survival rate was 89.5%, 80.5%, 80.5%, and 43.0%, respectively. Conclusions: Herein, we present imaging and pathologic findings of the case with review of the literature.