Syndromes for Thursday, June 4th, 2026

History

A 2-year-old child presented with a palpable abdominal mass. Initial ultrasound examination demonstrated a large heterogeneous abdominal tumorous lesion of uncertain origin. Clinical examination revealed associated aniridia, cryptorchidism, and hypospadias. Further imaging evaluation was performed for lesion characterization, determination of organ of origin, and staging. Subsequent CT examination demonstrated a well-defined large tumorous mass with heterogeneous enhancement, possible necrotic or hemorrhagic components arising from the parenchymal bridge of a horseshoe kidney with a “claw sign,” in which the surrounding renal parenchyma appears to wrap partially around the mass.

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Question

Which syndrome is most strongly associated with these findings?

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Correct answer

WAGR syndrome

Discussion

WAGR syndrome is a rare contiguous gene deletion syndrome caused by a deletion on chromosome 11p13 involving the WT1 and PAX6 genes. The acronym WAGR refers to the characteristic clinical features: Wilms tumor, Aniridia, Genitourinary anomalies, and Range of developmental delay/intellectual disability. The syndrome is most commonly diagnosed in early childhood, often after recognition of aniridia or development of a renal mass.

Children with WAGR syndrome carry a markedly increased risk of developing Wilms tumor, with reported lifetime risk approaching 40–60%. Therefore, early identification of syndromic features is essential because these patients benefit from regular renal ultrasound surveillance and multidisciplinary follow-up. In many cases, aniridia represents the earliest and most recognizable clinical finding and should always prompt consideration of an underlying syndromic association.

Genitourinary anomalies are common and may include cryptorchidism, hypospadias, gonadal dysgenesis, ambiguous genitalia, and renal anomalies. In the presented case, the coexistence of aniridia, cryptorchidism, and hypospadias provided an important clinical clue toward the diagnosis of WAGR syndrome even before definitive imaging characterization of the abdominal mass.

Imaging plays a central role in both diagnosis and management. Ultrasound is usually the first-line modality for screening and initial assessment of abdominal masses in children. Cross-sectional imaging with CT or MRI is subsequently required for precise characterization of the lesion, determination of renal origin, local staging, vascular evaluation, and assessment of metastatic disease.

An additional distinctive feature in this patient was the presence of a Horseshoe kidney, from which the Wilms tumor originated. Tumors arising in horseshoe kidneys are uncommon and may pose diagnostic and surgical challenges because of abnormal renal anatomy, aberrant vascular supply, and atypical tumor location within the parenchymal bridge/isthmus. Recognition of these anatomic variations is crucial for surgical planning.

This case emphasizes the importance of correlating imaging findings with physical examination and syndromic features in pediatric oncology. Recognition of the characteristic constellation of findings in WAGR syndrome may facilitate earlier diagnosis, appropriate genetic counseling, surveillance strategies, and optimized multidisciplinary treatment planning.

References

• 1. Fischbach BV, Trout KL, Lewis J, Luis CA, Sika M. WAGR Syndrome: A Clinical Review of 54 Cases. Pediatrics. 2005;116(4):984–988. 2. Hol JA, Jongmans MCJ, Sudour-Bonnange H, et al. Clinical Characteristics and Outcomes of Children With WAGR Syndrome and Wilms Tumor: The 30-Year SIOP-RTSG Experience. Cancer. 2021;127(4):628–638. 3. Luu DT, Duc NM, Tra My TT, Bang LV, Lien Bang MT, Van ND. Wilms' Tumor in Horseshoe Kidney. Case Rep Nephrol Dial. 2021;11(2):124–128. doi:10.1159/000514774.