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This article has been peer reviewed. It was published in: Journal of Clinical Imaging Science.

Volume 4, Issue 1, January/March 2014, Article number 126050..

The published version is available at DOI: 10.4103/2156-7514.126050

Copyright © 2014 Mardekian SK.


Extraosseous Ewing's sarcoma/peripheral neuroectodermal tumors (ES/PNETs) are rare neoplasms that account for approximately 10%-15% of soft tissue sarcomas in children and 5% of soft tissue sarcomas in adults. Primary spinal, extraosseous, intradural ES/PNETs are even less common. The diagnosis of ES/PNET is extremely challenging, because the tumor can have a nonspecific radiologic appearance, and the histologic features are shared by many other "small round cell tumors." Thus, ES/PNET should be included in the radiologic and pathologic differential diagnosis, even in older patients and in unusual tumor sites. We report two cases of spinal, extraosseous, intradural ES/PNETs in adults who presented with back pain. Magnetic resonance imaging revealed contrast enhancing, intradural lesions in the area of the conus medullaris. The tumor in Case 1 was partially intramedullary, while the tumor in Case 2 was exclusively extramedullary. In both cases, the radiologic and intraoperative surgical impression favored ependymoma. The diagnosis of ES/PNET was established in both cases by histopathologic, immunohistochemical, and molecular analysis.

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