Renal cell carcinoma in the contralateral kidney with TFE3 gene translocation following chemotherapy for childhood nephroblastoma: A case report and literature review

KEY CLINICAL MESSAGE: Renal cell carcinoma as a secondary malignant neoplasm is relatively rare; however, the possibility of secondary renal cell carcinoma following chemoradiotherapy for childhood nephroblastoma should be considered. ABSTRACT: The occurrence of secondary renal cell carcinoma (RCC) following chemoradiotherapy for nephroblastoma is relatively rare, especially in microphthalmia transcription factor family translocation renal cell carcinoma. A 13‐year‐old Japanese male was referred to our department for treatment of a right kidney mass. The patient had undergone open left nephrectomy and adjuvant chemotherapy for nephroblastoma, 12 years before. Diagnostic imaging revealed a tumor in the right kidney and a lesion suspected to be metastasis in the left eighth rib. Chromophobe RCC or translocation RCC was suspected from the imaging pattern. TNM classification was cT1aN0M1, and the clinical stage was IV. Partial nephrectomy by robot‐assisted surgery for the right renal tumor and resection of the left eighth rib were performed. Pathologically, the renal tumor was diagnosed as translocation RCC, and the rib lesion demonstrated no evidence of malignancy. We are currently undergoing imaging follow‐up and the patient has been recurrence‐free for 15 months. In this study, we present a rare case of secondary translocation RCC after successful treatment of nephroblastoma.