title: Two Cases of Spinal, Extraosseous, Intradural Ewing's sarcoma/Peripheral Neuroectodermal Tumor: Radiologic, Pathologic, and Molecular Analysis.
abstract: 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.
authors.affiliation: Department of Pathology, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
authors.forename: Stacey K
authors.initials: SK
authors.lastname: Mardekian
authors.affiliation: Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
authors.forename: Ashish
authors.initials: A
authors.lastname: Gandhe
authors.affiliation: Department of Laboratory of Pathology, National Cancer Institute, United States.
authors.forename: Markku
authors.initials: M
authors.lastname: Miettinen
authors.affiliation: Department of Laboratory of Pathology, National Cancer Institute, United States.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Pack
authors.affiliation: Department of Pathology, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Curtis
authors.affiliation: Department of Laboratory of Pathology, National Cancer Institute, United States.
authors.forename: Ziedulla
authors.initials: Z
authors.lastname: Abdullaev
keywords: Ewing sarcoma/peripheral neuroectodermal tumor; intradural spinal neoplasms; peripheral neuroectodermal tumors