Case Report
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. May 26, 2024; 12(15): 2606-2613
Published online May 26, 2024. doi: 10.12998/wjcc.v12.i15.2606
Primary Ewing sarcoma of the kidney mimicking cystic papillary renal cell carcinoma in an older patient: A case report
Suhong Kim, Jongsoo Park, Young Hwii Ko, Hee Jung Kwon
Suhong Kim, Jongsoo Park, Department of Radiology, Yeungnam University, Daegu 42415, South Korea
Young Hwii Ko, Department of Urology, Yeungnam University, Daegu 42415, South Korea
Hee Jung Kwon, Department of Pathology, Yeungnam University, Daegu 42415, South Korea
Author contributions: Kim S and Kwon HJ completed conceptualization; Kwon HJ and Ko YH completed data curation; Kim S, Park J and Kwon HJ wrote the original draft; Kim S reviewed and edited the mauscuript; All authors have read and agreed to the published version of the manuscript.
Supported by Yeungnam University, No. 223A580026.
Informed consent statement: The requirement for informed consent was waived by the board because of the patient’s death.
Conflict-of-interest statement: The authors declare no conflicts of interest.
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 that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: Hee Jung Kwon, MD, PhD, Assistant Professor, Department of Pathology, Yeungnam University, 170 Hyeonchung-ro, Nam-gu, Daegu 42415, South Korea.
Received: January 8, 2024
Revised: March 6, 2024
Accepted: April 7, 2024
Published online: May 26, 2024

Ewing’s sarcoma (ES) is a neuroectodermal tumor that typically occurs in the bones and soft tissues of children and young adults. Primary renal ES is rare; only a few cases and a small case series have been documented, and only four cases involved primary renal ES in older people (> 65 years old).


Herein, we describe the radiological and pathological features of primary renal ES in an older person. A 76-year-old man complained of poor oral intake and was found to have a large cystic renal mass with indistinct margins on computed tomography. Ultrasound-guided biopsy revealed that the tumor contained small round blue cells. The patient underwent a right radical nephrectomy. The tumor cells showed diffuse membranous CD99, and nuclear friend leukemia integration 1 transcription factor and NK2 Homeobox 2. Fluorescence in situ hybridization revealed EWSR1 translocation. Postoperatively, 18F-fluorodeoxyglucose positron emission tomography revealed no evidence of metastasis. The patient was diagnosed with primary renal ES. Six months following the surgery, local recurrence and distant metastasis were observed. Primary renal ES is rare and often lethal in older individuals. The specific imaging findings are unknown, and treatment protocols have not been standardized.


This case report describes the radiological and pathological features of primary renal ES in an older person.

Keywords: Ewing sarcoma, Elder, Renal, Kidney, Neuroectodermal, Case report

Core Tip: Primary renal Ewing’s sarcoma (ES) is extremely rare, whereas shown aggressive radiological features and poor outcome. It is important to consider primary renal ES in the differential diagnosis when renal mass shown indistinctive margin and necrosis/hemorrhage in older patients. Primary renal ES undergo surgical resection and receive adjuvant chemotherapy. Moreover, radiation therapy is efficient for local recurrence.