title: Primary renal synovial sarcoma: computed tomography imaging findings.
abstract: BACKGROUND
  A synovial sarcoma arising from the kidney is extremely rare. To date, few data are available on their radiological features.
  
  
  OBJECTIVE
  To identify the computer tomography (CT) imaging findings of primary renal synovial sarcomas (PRSSs).
  
  
  METHODS
  Five cases of PRSS confirmed by histopathological and cytogenetic studies were retrospectively analyzed. All patients had undergone unenhanced and multiphase enhanced CT examinations (one patient underwent CT twice). The CT characteristics, including shape, size, margin, attenuation, and enhancement pattern after intravenous contrast medium injection, were analyzed.
  
  
  RESULTS
  The study involved two female and three male patients (mean age, 27.4 years; range, 15-43 years). Unenhanced CT showed completely or partly well-defined masses, with heterogeneous (n = 5) or homogeneous (n = 1) patchy low density. On multiphase contrast-enhanced CT, in five of the six CT examinations, the tumors appeared as solid-cystic masses with cyst walls or pseudo-capsules, and demonstrated moderately heterogeneous (n = 5) and/or septate enhancement (n = 2), with a "rapid wash-in and slow wash-out" pattern of enhancement in the solid component. Only one tumor showed a simple cyst appearance and developed an irregular, intratumoral, septate soft density 8 months later. A renal vein and inferior vena cava thrombus was noticed in one patient, while lymphadenopathy was not observed in any patient.
  
  
  CONCLUSIONS
  PRSS should be included in the differential diagnosis when an adolescent or young adult presents with a renal neoplasm appearing as a solid-cystic mass with well-defined borders, a cystic wall or pseudo-capsule, heterogeneous or septate enhancement, a "rapid wash-in and slow wash-out" pattern of enhancement in the solid component, and no sign of lymphadenopathy.
authors.affiliation: Imaging and Interventional Radiology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, PR China.
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Lv
authors.affiliation: Department of Medical Imaging, The First Affiliated Hospital of Gannan Medical University, Ganzhou, PR China Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors.forename: Ying-Wei
authors.initials: YW
authors.lastname: Qiu
authors.affiliation: Imaging and Interventional Radiology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, PR China.
authors.forename: Lu-Jun
authors.initials: LJ
authors.lastname: Han
authors.affiliation: Department of Medical Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Cao
authors.affiliation: Department of Pathology, Sun Yat-sen University Cancer Center, Guangzhou, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Imaging and Interventional Radiology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, PR China.
authors.forename: Zhen-Yin
authors.initials: ZY
authors.lastname: Liu
authors.affiliation: Department of Medical Imaging Center, NanFang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Xue-Lin
authors.initials: XL
authors.lastname: Zhang
authors.affiliation: Imaging and Interventional Radiology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, PR China.
authors.forename: Pei-Qiang
authors.initials: PQ
authors.lastname: Cai
authors.affiliation: Imaging and Interventional Radiology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, PR China li2@mail.sysu.edu.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007472:Iohexol / Q000031:analogs & derivatives; D007668:Kidney / Q000000981:diagnostic imaging; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods; D012189:Retrospective Studies; D013584:Sarcoma, Synovial / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide
keywords: Synovial sarcoma; computed tomography; kidney