CASE REPORT article
Front. Pediatr.
Sec. Pediatric Oncology
Volume 13 - 2025 | doi: 10.3389/fped.2025.1602157
Undifferentiated Small Round Cell Sarcomas in the Retroperitoneal Space in A 12-year-old Female:A Rare Case Report
Provisionally accepted
- 1Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
- 2Ya'an People’s Hospital, Yaan, Sichuan Province, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Undifferentiated small round cell sarcoma (USRCS) is an extremely rare and highly aggressive group of malignant neoplasms affecting bones and soft tissues. USRCSs, particularly extraosseous variants pose significant diagnostic challenges due to their rarity, similar clinicoradiological features, nonspecific morphology and the necessity for comprehensive molecular analyses. This paper discusses a rare interesting case of retroperitoneal USRCS in a 12year-old female with a five-day history of diarrhea and slight right lower abdominal pain. Hematological profile, renal function test, liver function test and tumor markers were in normal limits. Preoperative imaging revealed a well-defined, highly vascularized mass in the lower right retroperitoneal space, featuring patchy calcification and osseous and fatty components that compressed the right ureter, causing obstructive hydroureteronephrosis. Given the clinical and imaging findings. The lesion was initially misdiagnosed as a benign teratoma. However, postoperative pathology and genetic testing confirmed USRCS, remarkably, the Ki-67 index was only 10%. The patient did not undergo any additional postoperative treatment and achieved long-term survival. Despite USRCS in the retroperitoneal space with calcification has been reported, we believe this is the first published case of USRCS with calcification and osseous and fatty components mimicking teratoma. The case is important in that it demonstrates the unusual imaging appearance of retroperitoneal USRCS.
Keywords: Undifferentiated small round cell sarcoma, Teratoma, Retroperitoneal Space, CT, EWSR1 translocation
Received: 28 Mar 2025; Accepted: 05 Aug 2025.
Copyright: © 2025 Liu, Liu, Li, Deng and Wu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dan Liu, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.