Ewing's sarcoma in the spinal canal of T12-L3: A case report and review of the literature.

Primary Ewing's sarcoma (ES) is rare, especially when it occurs in the spinal canal during middle or old age. The rarity of Ewing's sarcoma breakpoint region 1 fusion-negative ES has been reported in the literature. The present case report describes a 60-year-old Chinese patient who was diagnosed with ES originating from the spinal canal in 2016. The patient was hospitalized with pain resembling electric shock in the waist and buttocks, which occurred intermittently for 1 month, and incontinence for 1 week. Magnetic resonance imaging demonstrated multiple inhomogeneous, oval-shaped nodules in the intradural and cauda equina spaces of T12-L3. The largest nodule was ~23×11×10 mm. The patient underwent right adrenal tumour resection. A histopathologic examination of the focal area revealed that the tumour consisted of small, circular haematoxylin stained cells that formed typical Homer-Wright rosettes. Immunohistochemical analysis confirmed that the patient suffered from ES due to positive staining for membranous cluster of differentiation 99 (CD99), cytokeratin (CK) and nuclear foetal-liver infusion 1 (FLI-1). In conclusion, the histopathological presence of Homer-Wright rosettes and immunohistochemical markers such as CD99, FLI-1 and CK are valuable factors for the diagnosis of ES, although cytogenetic analysis is considered the gold standard. Complete surgery is the most effective treatment option for ES treatment. Adjuvant radiotherapy and combination chemotherapy can also improve the survival rate of patients postoperatively.