Ewing’s sarcoma/primitive neuroectodermal tumor (ES/PNET) of the bladder in an adolescent: a case description
Letter to the Editor

Ewing’s sarcoma/primitive neuroectodermal tumor (ES/PNET) of the bladder in an adolescent: a case description

Jingyi Tan, Jie Liang, Ligong Lu

Department of Interventional Medical Center, Zhuhai Hospital Affiliated with Jinan University (Zhuhai People's Hospital), Zhuhai, China

Correspondence to: Ligong Lu, MD, PhD. Department of Interventional Medical Center, Zhuhai Hospital Affiliated with Jinan University (Zhuhai People's Hospital), 79 Kangning Road, Zhuhai 519000, China. Email: Silencetan9bts@163.com.

Submitted Aug 17, 2022. Accepted for publication Jan 06, 2023. Published online Feb 07, 2023.

doi: 10.21037/qims-22-867


Extraosseous Ewing’s sarcoma/primitive neuroectodermal tumors (ES/PNET) are a relatively rare group of malignant tumors (1,2) that occur in children and adolescents aged between 10–20 years (3). ES/PNET are highly aggressive and generally portend poor prognoses (4) because of the lack of clear clinical symptoms during the early stages. These tumors frequently occur in the extremities and retroperitoneum (5,6), and are seldom in the internal organs. ES/PNET of the bladder is rare, with only a few reports available at present (7,8). We report a case of primary ES of the bladder that occurred in a 19-year-old female.

Case presentation

A 19-year-old female patient was admitted to our hospital after experiencing gross hematuria without concomitant urinary frequency, urgency, painful urination, and blood clots for 1 week. Urine samples were routinely collected on admission, and the red blood cell count was 7,796/µL. The patient had been smoking for the previous year and had no family history of tumors.

Outpatient ultrasound suggested a left ureteral end cyst with abnormal internal echogenicity and clot but did not exclude the possibility of a tumor. Contrast-enhanced ultrasound (CEUS) suggested mixed (predominantly solid component) left end ureteral occupancy (Figure 1A). Computed tomography (CT) enhancement showed a cystic and solid mass in the lower left ureter, indicating the presence of tumor lesions. Magnetic resonance imaging (MRI) suggested that the left ureteral bladder wall was occupied, suggesting the possibility of a ureteral cyst combined with hemorrhage (Figure 1B,1C).

Figure 1 The imaging findings of the lesion. (A) Mixed echogenic mass at the left ureteral orifice in the bladder triangle with CDFI showing a few dotted streaks of blood flow signals in and around it. (B,C) T2WI with predominantly low signal and a thin strip of slightly high signal area. The bladder wall signal is at the edge of the lesion, with low DWI signals. (D) Microscopic infiltration and growth of small round tumor cells with higher nuclear plasma and darker nuclear chromatin (HE ×40). CDFI, Color Doppler flow imaging; T2WI, T2 weighted imaging; DWI, diffusion-weighted imaging; HE, hematoxylin-eosin staining.

The patient then underwent cystoscopy and transurethral resection of bladder tumor (TURBT). Intraoperatively, the lesioned tissue had old hemorrhage and hematoma. Pathological examinations indicated microscopic infiltration and growth of small round tumor cells with higher nuclear plasma and darker nuclear chromatin (Figure 1D). Immunohistochemical staining of the paraffin tissue block A8 indicated that the lesion was positive for CD99, FLI1, Vimentin (+), SYN (focal weak), NSE (focal weak), β-catenin (cytosolic and cytoplasmic), INI-1, CD117, and Ki-67 (~40%), and negative for CgA, CK7, CK20, CK-pan, EMA, P63, GATA3, S100p, HCG, CD56, S100, Desmin, SMA, Myo-D1, Myogenin, and LCA. These findings were typical of extraosseous ES/PNET. The patient received gemcitabine infusion chemotherapy after surgery and was not subjected to further treatment. Notably, there was no sign of recurrence during the two years of follow-up.

All procedures performed in this study were in accordance with the ethical standards of the institutional and national research committee(s), and the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.


ES/PNET is a rare primary small round cell malignancy. It is difficult to establish clear guidelines for its management and treatment because of the minuscule number of reported cases. Its preoperative diagnosis is further complicated by the lack of specific imaging characteristics. Definitive diagnosis relies on postoperative pathology, immunohistochemistry, and genetic analysis. Early diagnosis and treatment of ES/PNET patients are thus highly challenging.

The case described in this report is of a 19-year-old female with clinical hematuria and hydronephrosis. The patient had a large lesion of approximately 55 mm ×36 mm, and had clear borders, irregular morphology, and convex growth towards the internal bladder. The lesion was close to the left ureteral bladder entrance, causing continuous compression to the left kidney and left ureteral fluid. The appearance of the lesion was very confusing on MRI, with significant low signals in T2WI and the center of DWI. The lesion had circumferential high signal at the edges, and T1WI showed equally high signal, slightly higher than the surrounding muscle signal. The internal signal of the lesion was more like a hematoma, and was also reflected in the surgical records. The pattern had a mild enhancement during the arterial phase, peaking during the venous phase, and decreasing during the delayed phase, with a net CT increase of approximately 8–29 HU. MRI showed discontinuous circumferential enhancement of the lesion with a significant visible gap in the right anterior.

In the previously reported cases (Table 1), the youngest patient was 10 years old, the oldest was 81 years old, bringing the mean age to 45 years. Notably, only one patient reported massive bleeding (25). Many patients had tumors on the right side of the bladder (7/21). In particular, there was extrinsic bladder protrusion towards the pelvis and the lesions were larger in most cases. However, the previous reports did not elaborate more on the imaging presentation. The imaging presentation of extraosseous Ewing sarcoma is not specific and may vary depending on the site. Generally, cystic necrosis is more common, calcification is rare, and pseudo-envelope may be present. Reinforcement varies depending on the site of occurrence and is mostly heterogeneous and variable (28,29). Ewing sarcoma of the bladder is rare but is more malignant and needs to be differentiated from the common uroepithelial carcinoma of the bladder. Based on the documented cases, Ewing sarcoma in the bladder seems to be common among middle-aged persons and young adults, while general uroepithelial carcinoma is common among middle-aged and older men. Notably, smoking is an important risk factor in both. CT enhancement demonstrates that there is progressive strengthening during uniform strengthening, with the most significant strengthening amplitude happening during the arterial phase (30). Of note, the final diagnosis of this disease relies on pathology because there are cases of ES combined with epithelial carcinoma. The imaging presentation of ES combined with epithelial carcinoma is somewhat different from that of most extraosseous ES because of the interference of massive bleeding. The descriptions of more new cases are thus necessary to improve the existing knowledge and experience.

Table 1

Reference cases of ES/PNET of the bladder

References Sex/age Symptoms Diagnostic Tumor size (mm) Local Surgery
Present case F/19 Gross hematuria US, CT, MRI 55×36 Left posterior TURBT
Sueyoshi et al. (9) M/10 Polyuria, lower-abdominal swelling US, CT 135×131×129 Right side Double J tube + partial cystectomy
Osone et al. (10) M/10 Dysuria, hematuria, hematuria, fever US, CT, cystoscope 10 Base TURBT
Rao et al. (11) F/14 Dull pain, lower-abdominal lump US, CT, needle biopsy 150×120×75 Posterior Partial cystectomy
Gousse et al. (12) F/15 Hematuria IVP, cystoscopy 30×20×20 Right anterior lateral TURBT
Lopez-Beltran et al. (13) F/21 Frequency, dysuria, hematuria US, cystoscope biopsy 90×80×60 The posterior and right and left sides Cystectomy + TH + BSO
Banerjee et al. (14) M/21 Frequency, dysuria, hematuria IVP, cystoscopy 80×60×40 Right side Cystectomy
Vallonthaiel et al. (15) F/27 Frequency, hematuria US, CT 103×98×47 Left anterior and lateral TURBT
Lam et al. (16) F/30 Polyuria, hematuria US, MRI 64×94×77 Right side TURBT + cystectomy + Indiana pouch
Tonyalı et al. (17) F/38 Hematuria CT 40×26×25 Right side TURBT + cystectomy + TH + BSO + ileal conduit
Desai (18) F/38 Hematuria Cystoscope 120×70×35 Posterior and right and left Cystectomy + TH + BSO
Gao et al. (8) F/45 Frequency, urgency, dysuria US, CT, cystoscope 30 Right neck TURBT + cystectomy + TH + ileal conduit
Busato et al. (19) F/52 Frequency, dysuria, pelvic pain, hematuria US, cystoscope 33×15×22 Right base TURBT
Colecchia et al. (20) F/61 Hydronephrosis, renal failure CT, cystoscope biopsy
Mentzel et al. (21) M/62 Dark urine, fever, backache, AUR MRI 140×100×100 TURBT + nephrostomy
Liu et al. (7) M/64 Abdomen dull pain CT 60×50 Left lateral out of bladder
Okada et al. (22) M/65 Hematuria, dysuria US, CT, cystoscope 50 Left posterior TURBT + cystectomy
Al Meshaan et al. (23) F/67 Hematuria, fever, hydronephrosis US, CT, cystoscope 30×25×10 Posterior TURBT + partial cystectomy
Ellinger et al. (24) M/72 Hematuria, oliguria MRI TURBT
Zheng et al. (25) M/74 Frequency, dysuria, hematuria CT Neck TURBT
Zhang et al. (26) F/78 Gross hematuria, blood clot, urinary frequency, urgency CTU 63×44 Right posterior TURBT
Krüger et al. (27) M/81 Lymphedema, fatigue, urge, incontinence US, CT TURBT + nephrostomy

ES/PNET, Ewing’s sarcoma/primitive neuroectodermal tumor; F, female; M, male; US, ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; TURBT, transurethral resecting of bladder tumour; IVP, intravenous urography; TH, total hysterectomy; BSO, bilateral salpingo-oophorectomy; AUR, acute urinary retention; CTU, computed tomography urography.


We would like to thank MogoEdit (https://www.mogoedit.com) for its English editing during the preparation of this manuscript.

Funding: None.


Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-22-867/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy and integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and national research committee(s), and the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.


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Cite this article as: Tan J, Liang J, Lu L. Ewing’s sarcoma/primitive neuroectodermal tumor (ES/PNET) of the bladder in an adolescent: a case description. Quant Imaging Med Surg 2023;13(4):2758-2762. doi: 10.21037/qims-22-867

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