Primary Extraosseous Spinal Ewing Sarcomas: Should We Be More Aware About Diagnosis?

Study Design: Single-center retrospective study.
Objective: We discuss the widespread misdiagnosis of primary extraosseous spinal Ewing Sarcomas (PESES) to begnin tumors leading to poor treatment.
Summary of Background Data: PESES is a particular entity of spinal Ewing sarcoma (SES) appearing in a similar shape and features to benign tumors such as schwannomas. This imaging mimicry and subsequent possible misdiagnosis lead to primary surgery, without neoadjuvant chemotherapy, which remains deleterious for survival and progression.
Methods: We identified a total of 13 patients: seven women (53.8%) and six men operated between 2001 and 2018 for PESES and initially misdiagnosed as schwannomas or ependymomas.
Results: The mean age of our series was 35.8 years (range, 18.1-47.2 years). The first clinical symptom was neuralgia (61.5%) followed or associated with nerves deficits (38.5%). Median progression-free survival (PFS) was 31.7 months (SD 5.8). Tumor recurrence rates at 1 and 3 years were respectively 21.2% (SD 3.1) and 60.1% (SD 15.8). Median overall survival (OS) was 61.5 months (SD 16.27). The 1-year, 2-year, and 5-year survival estimates were 100.0%, 88.9% (SD 10.5), and 44.4% (SD 16.6). Six patients (46.13%) died following their SES. In univariate analyses, patients with metastastic PESES had a significantly lower OS than others (41.2 months, P = 0.03).
Conclusion: PESES must be ruled out at diagnosis of a spinal tumor when facing a fast-growing lesion with neurological deficits in a young adult. Thoracoabdominopelvic extension should be carried out. Presurgical biopsy must be performed. In case of PESES, neoadjuvant chemotherapy must be established before considering surgical intervention.Level of Evidence: 4.
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