Adult Recurrent Wilms’ Tumor Presenting as a Large Mass: A Case Report and Current Literature Review

Abstract

Wilms tumor (WT) is the most common renal malignancy in children but can be challenging to diagnose in adults because its clinical and imaging features often mimic those of renal cell carcinoma (RCC). Most diagnoses are made incidentally following nephrectomy performed for suspected RCC. Due to the lack of established adult-specific treatment guidelines, management typically follows pediatric protocols. This report presents the case of a 26-year-old woman who presented with abdominal pain, weight loss, and fatigue. Imaging revealed a large, irregular mass in the left kidney, which was confirmed as WT after nephrectomy. She underwent radical nephrectomy followed by adjuvant chemotherapy, including doxorubicin, vincristine, and actinomycin D. After two years of follow-up, recurrence was detected, leading to a second surgery followed by radiotherapy. This case highlights the diagnostic and therapeutic challenges associated with adult WT and emphasizes the need for individualized treatment strategies tailored to each patient.

Wilms tumor (WT), also called nephroblastoma, is the most common form of kidney cancer in children, accounting for more than 90% of malignant renal tumors in the pediatric population and primarily affecting those under the age of 5.^[1] In contrast, WT is extremely rare in adults, with an incidence of less than 0.2 cases per million people each year.^[2] Although WT is usually found as a single tumor, about 10% of cases can be bilateral and associated with syndromic forms.^[3] Unfortunately, the clinical presentation and imaging findings of WT in adults are nonspecific, which may lead to misdiagnosis as renal cell carcinoma (RCC), the most common renal malignancy in adults. Because of its rarity, treatment based on pediatric protocols is often delayed, leading to less favorable outcomes compared with those in children with WT.

Case Report

A 26-year-old woman presented with a 2-month history of progressively worsening left-sided upper abdominal tenderness, involuntary weight loss, and fatigue. She had no significant past medical history, genetic disorders, or previous renal problems. On examination, the only notable finding was abdominal tenderness. Laboratory results showed normal hemoglobin, white blood cell, platelet, and serum creatinine levels, indicating no immediate health problems. Imaging studies, including CT scans of the chest, abdomen, and pelvis, revealed a large, irregular renal mass measuring approximately 15 cm (Fig. 1). The mass had both solid and cystic components and irregular borders. No distant metastases were observed on chest CT or PET scans (Fig. 2). The multidisciplinary uro-oncology team reviewed the case and recommended a biopsy, which revealed a malignant tumor with rosette-like structures suggestive of Wilms tumor as a possible diagnosis. Immunohistochemistry showed positive staining for panCK, Glypican 3, and PAX8, while markers such as WT1, CD45, and others were negative. Considering the size and complexity of the tumor, an open surgical approach was chosen. During left radical nephrectomy, the renal artery and vein were carefully isolated, clamped, and divided. Postoperative pathology confirmed WT with a triphasic pattern consisting of blastemal, epithelial, and stromal components, which was specific for WT. Additionally, rosette-like structures were observed, and invasion of the perirenal adipose tissue by the tumor was identified (Fig. 3). The tumor was confined to the kidney without involvement of the surrounding tissues. Surgical margins were negative. After surgery, the patient received six cycles of adjuvant chemotherapy with doxorubicin, vincristine, and actinomycin D, which were well tolerated. Follow-up imaging and blood tests over 2 years did not reveal any major complications. However, during routine follow-up, recurrent masses were detected in the left adrenal gland and inferior to the previous kidney site, invading the spleen, adrenal gland, and tail of the pancreas (Fig. 4). After multidisciplinary review, it was decided to perform open excision of the masses, splenectomy, and distal pancreatectomy. Pathology confirmed Wilms tumor with a 95% epithelial component, negative surgical margins, and no nephrogenic rests. Adjuvant radiotherapy was administered during the postoperative period, and no recurrence was detected on the PET scan performed 6 months postoperatively (Fig. 5). The patient continues to undergo follow-up. Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Figure 1.

Preoperative imaging; Axial section and PET section of contrast-enhanced CT performed due to renal mass. Heterogeneous mass formation measuring 15.5x13.5x9 cm in the left kidney.

Figure 2.

Second preoperative imaging of recurrent masses; coronal section of contrast-enhanced CT.

Figure 3.

Pathology images from the surgical specimen: a) Rosette-like structures, b) Tumor invasion into the perirenal adipose tissue.

Figure 4.

a) Post-splenectomy spleen material, b) Recurrent mass material.

Figure 5.

No mass was detected in the recurrence area on the FDG-PET performed at the 6-month follow-up after secondary surgery.

Discussion

Wilms tumor, despite being the most common pediatric renal malignancy, is exceedingly rare in adults, posing diagnostic, therapeutic, and surveillance challenges.^[4] For example, consider the case of a 26-year-old woman who was otherwise healthy and presented with nonspecific symptoms of increasing left upper abdominal pain, weight loss, and fatigue. Such symptoms may persist for two months, demonstrating the subtle manner in which adult WT may present and how easily it may be confused with other renal malignancies.^[5] Initially, imaging studies showed a large solid-cystic renal mass with irregular borders, which again led the radiologist to suspect a diagnosis of RCC. Upon histopathological examination, however, the classical triphasic components of WT (blastemal, epithelial, and stromal), along with rosette-like structures, were identified.^[6] Positive immunohistochemical staining for panCK, Glypican-3, and PAX8 supported the diagnosis of WT, while WT1 negativity was consistent with adult WT subtypes described in the literature.^[7] Although previous studies have reported that imaging alone is often inadequate for definitively diagnosing Wilms tumor, recent evidence indicates that MRI may offer a promising approach to improving diagnostic accuracy.^[8]

Adult WT is often diagnosed late and is usually incorrectly classified as RCC. This emphasizes the need for a high index of suspicion and histological confirmation.^[5] In this case, the surgical margin was negative after nephrectomy, and the tumor was confined to the kidney. However, two years later, local recurrence was noted, with the tumor invading the adrenal gland, spleen, and tail of the pancreas. The recurrent tumors were predominantly epithelial, suggesting possible histological evolution over time.^[9] Treatment was based on pediatric protocols, including radical nephrectomy and adjuvant chemotherapy with doxorubicin, vincristine, and actinomycin D, which the patient tolerated well. Evidence from the literature indicates that adult patients with Wilms tumor who are treated according to pediatric protocols may achieve a 5-year overall survival rate of approximately 80%.^[10] Nevertheless, delayed diagnosis, increased treatment-related toxicity, and variations in histological subtype can negatively influence outcomes in adults.^[11] Recent case reports have highlighted the potential benefits of targeted therapies and early initiation of chemotherapy.^[12-14] Collectively, these findings underscore the importance of an individualized, multidisciplinary, and protocol-guided approach to the management of adult Wilms tumor. This case demonstrates the aggressive behavior and high potential for recurrence of adult WT.

Conclusion

Adult WTs are rare; however, physicians should consider this diagnosis when evaluating renal masses. Diagnosis may be delayed because of the often nonspecific clinical and radiological findings. Early diagnosis, thorough histopathological evaluation, and a multidisciplinary management approach are crucial for improving treatment outcomes. Because recurrence can occur years after initial treatment, as demonstrated in our case, long-term follow-up is necessary. Treatment response and prognosis may depend on the histological subtype, and because there are no established adult-specific guidelines for this rare disease, reporting new cases remains essential for developing evidence-based treatment strategies.

Disclosures

Ethics Approval

This is a single case report, and therefore ethics committee approval was not required in accordance with institutional policies.

Informed consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Conflict of Interest

The authors declare that there is no conflict of interest.

Financial Disclosure

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Use of AI for Writing Assistance

No AI-assisted technologies (such as Large Language Models, chatbots, or image generators) were used in the preparation of this manuscript.

Authorship Contributions

Concept – C.S., O.N., A.Z.; Design – C.S., O.N.; Supervision – A.E., H.L.C., O.C.; Data collection &/or processing – C.S., A.Z.; Analysis and/or interpretation – C.S., O.N., A.E., H.L.C.; Literature search – C.S., O.N., H.L.C., A.E., O.C.; Writing – C.S., O.N.; Critical review – A.E., H.L.C., O.C.

Peer-review

Externally peer-reviewed.