Primary spinal epidural Ewing sarcoma: a case report and review of the literature.

Primary extraosseous Ewing sarcoma is a rare entity, especially in the spinal epidural site. Less than 20 cases have been reported in the literature. Here, we present a previously healthy 12-year-old boy who complained of low back pain, progressive gait disturbance and weakness of right lower extremity for nearly one month before admission. Magnetic resonance imaging showed one solitary posterior extradural mass, measuring 4 x 2.2 x 2.1 cm, with severe cord compression at the level from T7 to T9. The mass appeared hypo-intense on both T1-weighted and T2-weighted images and homogeneous contrast enhancement after injection of gadolinium. He underwent laminectomies of T8 and T9 and complete resection of the tumor. The pathology confirmed a diagnosis of Ewing sarcoma after immunohistochemical staining. His profound neurological deficits recovered well and no recurrence was discovered after adjuvant chemotherapy and radiotherapy. The relevant literature is reviewed and the limited cases are also analyzed.