A case report describes a rare instance of thoracic Ewing sarcoma presenting as acute spinal cord compression in a 20-year-old man with no significant medical history. The patient experienced 10 days of heaviness in both lower limbs and urinary incontinence. Examination revealed flaccid paraplegia with complete motor loss, a sensory level at the T10 dermatome, and a left paravertebral mass. Magnetic resonance imaging showed an extensive lesion involving the D10–D12 region of the thoracic spine. The mass extended into the spinal canal and left paravertebral soft tissues, producing significant spinal cord compression. The imaging findings were nonspecific, and a thoracoabdominal-pelvic CT scan found no other primary or metastatic sites. The patient underwent D10–D12 laminectomy and wide excision of the intraspinal and paravertebral components. His postoperative recovery was uncomplicated, and he experienced partial improvement in motor function. Histopathological examination confirmed Ewing sarcoma, a highly malignant tumor that generally affects children and adolescents and most often arises in the pelvis, chest wall, or long bones. Non-sacral spinal involvement is uncommon, and thoracic disease in a young adult is particularly rare. The patient subsequently received chemotherapy under the VAC protocol, stereotactic radiation therapy totaling 30 Gy in 10 fractions, and physical rehabilitation. Six months later, he developed headaches and exophthalmos. Brain MRI identified an orbital lesion with associated meningeal thickening, raising concern for disease progression or dissemination. The report emphasizes that prompt MRI evaluation and surgical decompression are important when neurological deficits occur, followed by coordinated chemotherapy and radiotherapy. Although localized Ewing sarcoma may have a more favorable prognosis, metastatic disease remains associated with poor outcomes.