Lower Extremity Weakness in an Adolescent Female - A Rare Presentation of Ewing Sarcoma.

Background: Ewing sarcoma, a rare cause of cord compression, is predominantly of osseous origin but can also originate in soft tissues. Soft-tissue manifestations account for <15% of all Ewing sarcoma tumors, and even fewer cases of Ewing sarcoma originating in the epidural space have been documented.

Case Report: A 19-year-old female presented to the emergency department for worsening low-back pain during the previous 6 months and numbness and weakness in her legs during the prior 2 weeks. Magnetic resonance imaging revealed an epidural mass at the L4-L5 level. Intravenous steroids were started for a presumed diagnosis of lymphoma. Orthopedic surgery consultants deferred computed tomography-guided biopsy of the mass out of concern for tumor seeding. Compression symptoms worsened to include foot drop and saddle anesthesia, prompting urgent radiation therapy. After the patient showed poor response to appropriate treatment for lymphoma, other malignant and infectious causes were considered. Biopsy was performed on day 3 of the patient's hospital stay, and by day 7, preliminary cytology results revealed Ewing sarcoma. Subsequent laminectomy and tumor resection produced immediate relief of pain, along with a gradual return of strength and sensation. The mass was found to be of soft-tissue origin and was classified as an extraosseous Ewing sarcoma. The patient was referred to a pediatric oncologist to complete the appropriate chemotherapy after diagnosis.

Conclusion: This case demonstrates how an uncommon manifestation of a rare disease can mimic a classic presentation of cord compression. Our aim is to bring awareness to this disease and to emphasize the importance of timely biopsy of any mass.