Case Report
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Oct 6, 2019; 7(19): 3098-3103
Published online Oct 6, 2019. doi: 10.12998/wjcc.v7.i19.3098
Primary renal synovial sarcoma: A case report
Huai-Jie Cai, Nan Cao, Wei Wang, Fan-Lei Kong, Xi-Xi Sun, Bin Huang
Huai-Jie Cai, Nan Cao, Wei Wang, Fan-Lei Kong, The Fourth School of Clinical Medicine of Zhejiang Chinese Medical University, Hangzhou 310053, Zhejiang Province, China
Xi-Xi Sun, Bin Huang, Department of Ultrasound, Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang Province, China
Author contributions: Cai HJ and Cao N participated in the design of the report, analyzed the data, and wrote the paper; Wang W and Kong FL collected the medical imaging materials; Sun XX and Huang B designed the report and performed the preliminary revision of the article.
Informed consent statement: Consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Bin Huang, MA, MSc, Chief Physician, Department of Ultrasound, Xixi Hospital Affiliated to Zhejiang Chinese Medical University, No. 2, Hengbu Road, Xihu District, Hangzhou 310023, Zhejiang Province, China.
Telephone: +86-571-86481593
Received: April 25, 2019
Peer-review started: May 7, 2019
First decision: May 31, 2019
Revised: June 20, 2019
Accepted: July 3, 2019
Article in press: July 3, 2019
Published online: October 6, 2019

Synovial sarcoma, a rare mesenchymal tumor type with unclear histological origin and direction of differentiation, accounts for 6%–10% of soft tissue tumors. It is mainly located near the joints and tendons of the limbs, and occurs primarily in children or young adults. Primary renal synovial sarcoma (PRSS) is very rare, accounting for approximately 1% of synovial sarcomas. It is a spindle cell tumor type affecting mesenchymal tissue, and has morphological, genetic, and clinical characteristics, and a certain degree of epithelial differentiation. It is highly malignant and has the fourth highest incidence among soft tissue sarcomas. Here, we report a case of PRSS and share some valuable information about the disease.


A 54-year-old male patient was admitted to the hospital for a space-occupying lesion in the right kidney for 2 d upon ultrasound examination. The patient had no cold or fever; no frequency, urgency or pain of urination; and no other discomfort. The results of a hemogram, blood biochemistry, and tumor markers were in the normal range. The patient was examined by computed tomography (CT), which indicated the presence of a soft tissue density shadow with a diameter of approximately 6.8 cm in the right renal pelvis area, showing uneven enhancement. Ultrasound indicated a cystic solid mass of approximately 6.8 cm × 6.5 cm in the right kidney, with an unclear boundary and irregular shape. Meanwhile, color Doppler flow imaging showed dotted blood flow signals in the periphery and interior. Contrast-enhanced ultrasound (CEUS) showed "slow in and fast out" hyperenhancement of the right renal mass after contrast agent injection. The postoperative pathological diagnosis was (right kidney) synovial sarcoma. Despite postoperative adjuvant chemotherapy, tumor recurrence was detected two years later.


PRSS is a rare malignant tumor. To date, no characteristic imaging findings have been observed. The diagnosis is confirmed primarily through postoperative pathological immunohistochemistry and SS18 (SYT) gene detection. In this case, CEUS was used preoperatively. We found that PRSS has the characteristic of "slow in and fast out" hyperenhancement, and its particular characteristics have diagnostic value. Postoperative adjuvant chemotherapy is not very effective.

Keywords: Renal synovial sarcoma, Ultrasonic imaging, Chemotherapy, Case report

Core tip: Synovial sarcomas are found mainly in the joints and tendons of the extremities, but rarely in the kidneys, and they are most common in children and young adults. Here, we report the imaging findings (notably contrast-enhanced ultrasound), histopathologic immunohistochemistry, and treatment of a case of primary renal synovial sarcoma. The purpose of this report is to help readers further understand this disease.