Primary Intracranial Ewing Sarcoma With EWSR1-FLI1 Gene Translocation Mimicking a Meningioma and a Multidisciplinary Therapeutic Approach: A Case Report and Systematic Review of Literatures

Abstract

Ewing sarcoma and peripheral primitive neuroectodermal tumor (ES/pPNET) is an undifferentiated malignant tumor that is most prevalent in children and young adults and often radiologically mimics a meningioma. A 38-year-old female patient visited our hospital with complaints of right-sided tinnitus, right hemiparesis, and imbalance. She underwent preoperative imaging and was subsequently diagnosed as having a meningioma on the petrous ridge. After partial resection, EWSR1-FLI1 gene fusion was confirmed, and she was diagnosed with ES/pPNET. The tumor was successfully treated using a multidisciplinary approach of adjuvant chemo- and radiotherapy. This case is noteworthy because it is an extremely rare case of an intracranial ES/pPNET, and it is worth sharing our clinical experience that the tumor was successfully treated through a multidisciplinary therapeutic approach even though complete resection was not achieved.

Keywords: EWSR1; Ewing sarcoma; FLI1; Meningioma; Peripheral primitive neuroectodermal tumor.

Fig. 1. Preoperative images of the patient: T1-weighted image (A), T2-weighted image (B), contrast-enhanced T1-weighted image (C), ADC map (D), and CBV map (E) of MRI; and ¹⁸F-FDG PET/CT (F). ADC, apparent diffusion coefficient; CBV, cerebral blood volume; FDG, fluorodeoxyglucose; PET/CT, positron emission tomography/computed tomography.

Fig. 2. Pathologic results of the patient. Tissue stained by hematoxylin and eosin (A), immunohistochemically stained by GFAP (B), VMA (C), CD99 (D), and vimentin (E), and tissue with fluorescence in situ hybridization using dual-color break-apart rearrangement probes which flank the EWSR1 breakpoint (F). Pseudorosette formation and rearranged chromosome 22 are annotated by white triangles (A) and arrows (B), respectively. GFAP, glial fibrillary acidic protein; VMA, vimentin antibodies; CD, cluster of differentiation.

Fig. 3. Postoperative images of the patient: T2-weighted image at POD 15 (A), CT at POD 31 (B), contrast-enhanced T1-weighted image 3 months after surgery (C), and contrast-enhanced T1-weighted image 10 months after surgery (D). POD, postoperative day.