en Radiology Radiology case report case report <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">Primitive neuroectodermal tumors (PNET) are a family of poorly differentiated malignant neoplasms of neuroectodermal origin. According to the location of origin, PNETs could be further categorized as central or peripheral. Peripheral PNET (pPNET) is an uncommon type that accounts for 1% of all soft tissue sarcomas and occurs outside the central and sympathetic nervous systems. Ovarian PNET is a very rare tumor with a high mortality rate. We report a case of pPNET originating from the pelvic cavity of a young woman. Ultrasound and Magnetic Resonance Imaging (MRI) findings demonstrated the presence of a high-grade malignant ovarian tumor. On microscopic evaluation, the tumor was composed of solid nests and sheets of small rounded cells, and on Immunohistochemical (IHC) evaluation, the tumor cells showed intense cell-membranous immunoactivity for MIC2 protein (CD99).</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">In the differential diagnosis of any invasive pelvic tumor in young women, pPNET should be considered.</span></span></span></span></span></span></span></span><br> &nbsp; Primitive Neuroectodermal Tumor (PNET), Ovary, Magnetic Resonance Imaging (MRI) findings, Tumor, Diagnosis 562 567 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-6457-2&slc_lang=en&sid=1 Sara Parviz srparviz@gmail.com 200319475328460089419 200319475328460089419 No Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran Fahimeh Zeinalkhani F_zeinalkhani@sina.tums.ac.ir 200319475328460089420 200319475328460089420 Yes Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran Masoumeh Gity p.giti@yahoo.com 200319475328460089421 200319475328460089421 No Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran Hamidreza   Saligheh Rad  h.saligherad@leeds.ac.uk 200319475328460089422 200319475328460089422 No Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Iran Anahita Fathi Kazerooni anahita.kazerooni@pennmedicine.upenn.edu 200319475328460089423 200319475328460089423 No Quantitative MR Imaging and Spectroscopy Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Iran Fatemeh Nili f_nili@yahoo.com 200319475328460089424 200319475328460089424 No Department Pathology, Tehran University of Medical Sciences, Tehran, Iran Peyman Kamali Hakim peyman_kamali_hakim@yahoo.com 200319475328460089425 0009-0000-9529-9081 No Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran Hadise Zeinalkhani H_zeinalkhani@yahoo.com 200319475328460089426 200319475328460089426 No Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran