Renal cell carcinoma (RCC) is a heterogeneous malignancy arising from renal tubular epithelial cells. While RCC is the most common renal tumor in adults, it is rare in children. Established risk factors RCC include immunosuppressive drugs such as cyclosporine, mycopheno-late, and prednisolone and acquired cystic kidney disease. Among pediatric patients, cytotoxic chemotherapy for malignancies, autoimmune disorders, and bone marrow transplantation may contribute to the development of translocation RCC. The incidence and risk factors for RCC in pediatric chronic kidney disease (CKD) and kidney transplant (KT) recipients remain unclear.

We report a case of a 13-year-old male KT recipient diagnosed with RCC. At 23 months of age, he presented with nephrotic syndrome (NS) that was refractory to treatment. A kidney biopsy revealed focal segmental glomerulosclerosis, cellular variant. Genetic testing for hereditary nephropathy was negative. Despite treatment with immunosuppressive agents—including corticosteroids, cyclosporine, cyclophosphamide, and rituximab—his NS frequently relapsed and progressed to end-stage renal disease two years after diagnosis of NS and underwent peritoneal dialysis for approximately two years before receiving a deceased donor KT, which was uneventful. Seven-years post-transplant, the patient presented with gross hematuria. Imaging revealed an approximately 8 cm, well-defined, round, complex cystic/necrotic mass in the right retroperitoneum. A right nephrectomy was performed, and histopathological analysis confirmed the diagnosis of papillary RCC. Additionally, a retrospective review of medical records from pediatric RCC patients (aged 0–18 years) at Samsung Medical Center between June 2014 and June 2024 was conducted. Total 22 patients were enrolled, and underlying diseases include Wilson disease (1), Crohn disease (1), congenital heart disease (1), malignancies (3), and KT (1).

Although RCC is rare in pediatric patients, those with a history of cytotoxic chemotherapy, CKD, or KT should be closely monitored, as RCC can remain asymptomatic until advanced stages. Further research is needed to establish screening guidelines for at-risk pediatric populations such as KT.