Adult-onset nephroblastoma in a male patient: a case report

Introduction

Nephroblastoma, also known as Wilms tumor, is the most common renal malignancy and the fourth most common overall malignancy diagnosed in children (1). 80% of patients with the diagnosis present before 5 years of age and it is more common in females than males, and in Black patients compared to White patients (2). The estimated incidence of adult nephroblastoma is 0.2 cases per million people annually (3). There are notable differences in the presentation of nephroblastoma in the pediatric versus adult population. In children, nephroblastoma often presents as a painless, palpable mass on examination, whereas adults more commonly present with hematuria and abdominal pain (4). In this report, we highlight a case of adult nephroblastoma from initial presentation to surgical management. We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-349/rc).

Case presentation

A Haitian Creole man in his twenties presented to the emergency department with complaints of intermittent hematuria and right flank pain over the course of the previous week. The patient recalled having an isolated episode of gross hematuria 3 years ago that self-resolved, so he did not pursue further intervention at that time. He denied any other systemic symptoms on presentation, including fevers, chills, abdominal pain, lower urinary tract symptoms, or unintentional weight loss. He had no past medical or surgical history and no abnormalities on physical examination. Initial laboratory evaluation demonstrated a white blood cell count of 5.1 cells/µL, hemoglobin (Hgb) of 13.4 g/dL, platelet count of 232,000/µL, creatinine of 0.99 mg/dL, and urinalysis was noteworthy for greater than 100 red blood cells per high-power field and large Hgb without any signs of infection. With the leading suspected diagnosis of nephrolithiasis, the emergency department initially obtained a non-contrast computed tomography (CT) abdomen/pelvis study. Unexpectedly, this revealed a large 11 cm × 11 cm × 9 cm mass arising from the upper pole of the right kidney. Urology was consulted at this time for further management.

To better characterize the mass, a contrast-enhanced CT abdomen/pelvis was obtained and it demonstrated the mass was internally enhancing with invasion of the right renal pelvis and compressive mass effect on the inferior vena cava (IVC), concerning for malignancy. To further evaluate whether the renal vein or IVC contained tumor thrombus, a magnetic resonance imaging (MRI) renal mass protocol was performed. This demonstrated no concern for vascular involvement (see Figure 1). Additionally, the MRI demonstrated a clear plane between the mass and the inferior aspect of the liver that was not appreciable on CT. A CT chest was also obtained for staging, which demonstrated no metastatic disease.

Figure 1 Magnetic resonance imaging with renal mass protocol demonstrating right upper pole mass in (A) axial and (B,C) two coronal views.

Medical oncology was subsequently consulted. Given his age, atypical radiographic presentation, and to evaluate whether neoadjuvant chemotherapy was indicated, the decision was made to proceed with a percutaneous renal mass core needle biopsy. This demonstrated positive staining for paired-box gene 8 (PAX8), Wilms tumor 1 (WT1), keratin acidic/epithermal (AE1/AE3), markers consistent with nephroblastoma (5). Furthermore, the biopsy stained positive for integrase interactor 1 (INI1), which ruled out renal rhabdoid tumor (6) and negative for B-rapidly accelerated fibrosarcoma (BRAF), which ruled out most benign metanephric adenoma (7). Following these results, the decision was made to proceed with radical nephrectomy without neoadjuvant chemotherapy.

The patient subsequently underwent an open right radical nephrectomy with regional lymph node dissection, including right hilar and right paracaval lymph nodes (see Figure 2). Intraoperatively, it was clear the entire upper pole of the kidney had malignant invasion abutting the lower edge of the liver. In this case, there was both an anterior and posterior renal artery, requiring us to encircle the anterior artery first before obtaining control of the renal vein, which did not appear pathologically involved on palpation. We then controlled the posterior artery and suture ligated the arteries and vein systematically. Careful dissection of the mass revealed a clear plane to spare the right adrenal gland, which also did not appear abnormal or involved.

Figure 2 Intraoperative specimens. (A) 804 g right kidney with 13.2 cm × 11 cm × 9 cm upper pole mass and bottom right staple indicating ureteral ligation; (B) right paracaval lymph node; (C) right hilar lymph nodes.

Postoperative pathology confirmed the excised mass to be nephroblastoma, 13.2 cm in greatest dimension with negative resection margins. There was an incidental 0.5 cm renomedullary interstitial cell tumor found within the specimen. Two right hilar lymph nodes and one right paracaval lymph node were all negative for metastatic disease. The tumor histology was favorable due to the absence of anaplasia. There was no invasion of the renal vein or sinus, nor was there tumor extension beyond the renal capsule. Since the patient underwent preoperative biopsy due to their abnormal presentation, this was considered stage 3 disease by Children’s Oncology Group (COG) guidelines. As such, medical oncology determined that adjuvant chemotherapy with 6 cycles of vincristine and dactinomycin was indicated due to the possible risk of tumor spillage. Prior to beginning chemotherapy, urology was again consulted as the patient desired fertility preservation. The patient’s semen analysis demonstrated azoospermia and thus, the decision was made to proceed with testicular sperm extraction (TESE). This was performed uneventfully at bedside under local anesthesia during the postoperative period. At 9 months postoperatively, the patient had completed his adjuvant chemotherapy regimen without evidence of disease on the most recent surveillance imaging. He tolerated chemotherapy without any significant side effects reported during clinic follow-up.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the 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.

Discussion

This case represents a rare presentation of nephroblastoma in the adult population. As shown in prior known adult cases, this patient presented with the symptoms of hematuria and flank pain (4). He may also have been at higher risk given his ethnicity (2). While there are established guidelines for the management of nephroblastoma in the pediatric population by the COG and International Society of Pediatric Oncology (SIOP) (8), this is not the case for adults, which portends worse clinical outcomes. This has been demonstrated by a study involving over 2,500 patients within the Surveillance, Epidemiology, and End Results (SEER) database that demonstrated a statistically significantly lower 5-year overall survival rate of 69% for adult nephroblastoma patients when compared to 94% for their pediatric counterparts (P<0.001) (9). While this patient is a younger adult, there are also reports of patients over 70 years old at the time of diagnosis. These patients appear to have a significantly worse prognosis, likely secondary to unfavorable histology and concurrent medical comorbidities (10). Of note, there are ongoing efforts by organizations such as the European Reference Network for Rare Urogenital Diseases and Complex Conditions (eUROGEN) that are promoting the collaboration of different European institutions to create guidelines for rare urologic diseases such as adult nephroblastoma (11).

An important point of consideration for this patient was the decision to obtain a renal mass biopsy as part of the patient’s workup. This decision was made after extensive interdisciplinary consultation with medical oncology, as the mass did not radiographically appear to be localized classic renal cell carcinoma or papillary tumor on imaging, where upfront nephrectomy without biopsy would be clearly indicated. Furthermore, prior implementation of SIOP protocols has demonstrated a benefit to preoperative biopsy for children with suspected Wilms tumor greater than 10 years of age in guiding appropriate clinical management (12). Specifically, biopsy was able to identify masses that were pathologically clear cell sarcoma or rhabdoid tumor, potentially requiring preoperative chemotherapy rather than upfront nephrectomy (12). Furthermore, this case involved a young patient who was mostly asymptomatic aside from intermittent pain, and who may have deferred the risks of surgery if the abnormal appearing mass was found to be of benign pathology on preoperative biopsy.

There are several key points to consider regarding the operative management of this patient case. First, the decision was made to pursue an open rather than minimally invasive approach for curative-oriented resection. This aligns with prior findings that open approaches may portend safer outcomes for resection of retroperitoneal masses of large volume (13). Second, another critical aspect of this case was the decision to spare the adrenal gland in the setting of a large upper-pole renal mass. In addition to the normal appearance and clear separation from the upper pole mass intraoperatively, there was no concern for metastasis beyond the kidney or preoperative radiographic involvement of the adrenal gland. Thus, adrenal-sparing surgery was performed as supported by the American Urological Association guidelines on renal masses (14). Finally, the decision was made to perform regional lymph node sampling despite minimal concern for nodal metastasis on preoperative imaging. Both COG and SIOP recommend lymph node sampling to ensure accurate disease staging for comprehensive treatment protocols after surgery (9). Prior literature has determined that there is a survival advantage for pediatric patients with even just 1 to 5 lymph nodes sampled (hazard ratio of 0.6, P=0.016) when compared to those with 0 lymph nodes sampled (15). As highlighted in Table 1, lymph node dissection for adults also appears to promote survival benefit (16-18). For adult nephroblastoma patients treated following pediatric guidelines, the survival rate has been shown to surpass 90% (19). However, this case does raise awareness of the need for more individualized approaches to definitively diagnose and manage adult nephroblastoma appropriately.

Conclusions

In the adult population, there is limited data on the appropriate management of nephroblastoma from diagnosis to intervention. We present the clinical course of a young adult male who underwent curative open radical nephrectomy and lymphadenectomy. At 9 months postoperatively, surveillance imaging shows no evidence of recurrence. Further investigation and collaboration are needed to create a standardized paradigm of management for nephroblastoma beyond the pediatric population.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-349/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-349/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-349/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 or 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/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the 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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