Single-nucleotide polymorphism in WT1 gene in a hyperplastic intralobar nephrogenic rest with botryoid protrusion.

Nephrogenic rests are nodular collections of undifferentiated renal blastema cells in the postnatal kidney that are recognized as putative precursor lesions of Wilms tumor. In this study, we report the case of a 3-year-old boy who was diagnosed with a hyperplastic intralobar nephrogenic rest extending through the renal pelvis and ureter. After radical nephrectomy, adjuvant chemotherapy was performed as done in stage II Wilms tumor. We also investigated the mutation of the WT1 gene and identified a related single-nucleotide polymorphism (rs16754). We consider that not only various genetic mutations but also single-nucleotide polymorphisms or other epigenetic factors might be involved in the development of Wilms tumor.