Ozge et al. Int J Pathol Clin Res 2019, 5:097 Volume 5 | Issue 2 DOI: 10.23937/2469-5807/1510097 ISSN: 2469-5807 International Journal of Pathology and Clinical Research Open Access Citaon: Ozge G, Dogan KR, Akgul A, Ali A (2019) Retroperitoneal Malignant Solitary Fibrous Tumor: A Case Report and Review of the Literature. Int J Pathol Clin Res 5:097. doi.org/10.23937/2469- 5807/1510097 Accepted: August 27, 2019: Published: August 29, 2019 Copyright: © 2019 Ozge G, et al. This is an open-access arcle distributed under the terms of the Creave Commons Aribuon License, which permits unrestricted use, distribuon, and reproducon in any medium, provided the original author and source are credited. Ozge et al. Int J Pathol Clin Res 2019, 5:097 • Page 1 of 6 • Retroperitoneal Malignant Solitary Fibrous Tumor: A Case Report and Review of the Literature Gumusay Ozge 1 , Koseoglu Resit Dogan 2* , Arici Akgul 2 and Akin Ali 3 1 Department of Medical Oncology, Tokat Gaziosmanpasa University School of Medicine, Tokat, Turkey 2 Department of Pathology, Tokat Gaziosmanpasa University School of Medicine, Tokat, Turkey 3 Department of General Surgery, Tokat Gaziosmanpasa University School of Medicine, Tokat, Turkey *Corresponding author: Koseoglu Resit Dogan, Department of Pathology, School of Medicine, Tokat Gaziosmanpasa University, Tokat, Turkey Abstract Background: Solitary fibrous tumor is a rare soft-tissue neoplasm that is capable of metastasis of fibroblastic/ myofibroblastic cell origin. Although most of the cases are pleural in origin, extrapleural locations are reported with increasing frequency. Extrapleural cases are mostly seen in retroperitoneal location. Malignant forms are much rarer. Case: A 61-year-old male patient was admitted with com- plaints of dysuria, low back pain and constipation. Radio- logical investigation revealed a retroperitoneal mass le- sion. The excised mass was macroscopically well-circum- scribed without capsule and was measured as 12 × 10 × 8 cm. The tumor was hypercellular and it contained necrosis areas. Peripheral soft tissue invasion was noted in the tu- mor. Tumor showed a vascular pattern that reminiscent of a hemangiopericytomatous pattern. Tumor were positive with CD34, bcl-2, EMA, vimentin, PAX8 and STAT6 in im- munohistochemical analysis. The case was diagnosed as retroperitoneal solitary fibrous tumor. The tumor was com- patible with the malignant category due to widespread ne- crosis, increased cellularity and high mitotic index. Conclusion: The hemangiopericytomatous pattern is seen in many soft tissue tumors. Many cases with extrapleural/ extrathoracal locations that were previously diagnosed as hemangiopericytoma are accepted to be solitary fibrous tumor by the advances of immunohistochemistry. With the increasing of awareness for extrapleural/extrathoracic solitary fibrous tumors, malignant SFT cases have been also reported more frequently. Histomorphological clues of malignancy are hypercellularity, nuclear pleomorphism, necrosis/hemorrhage and increased mitosis. In order to increase our knowledge about the clinicopatho- logical features and biological nature of these tumors, there is a need more cases of extrathoracal/extrapleural solitary fibrous tumor. Keywords Solitary fibrous tumor, Malignant features, Hemangiopericy- toma, STAT6, Retroperitoneal location Abbreviations SFT: Solitary Fibrous Tumor; SS: Synovial Sarcoma; GIST: Gastrointestinal Stromal Tumor; F-DFSP: Dermatofibrosar- coma Protuberans Showing Fibrosarcomatous Features; DLPS: Dedifferentiated Lposarcoma; HPF: High Power Field; WHO: World Health Organization; MRI: Magnetic Resonance Imaging Introducon Solitary fibrous tumor (SFT) accounts for less than 2 percent of all soſt ssue tumors [1]. Although the most common localizaon site is the pleura, the cases with extrapleural/extrathoracal locaon are increasingly being described [2]. Thirteen to fourteen percent of SFTs are extrapleural/extrathoracal. Localized cases of head, neck, intracranial, retroperitoneal regions, pelvis and genitourinary tract have been reported [3,4]. SFT cases with malignant histopathological features have also been reported in the literature. Here, we present a case of SFT who presented with retroperitoneal malignant histopathological features in a 61-year-old man. CASE REPORT Check for updates