Renal cell carcinoma with t(X;17)(p11.2;q25) in a 6-year-old Taiwanese boy.

Pediatric renal cell carcinoma (RCC) associated with ASPL-TFE3 gene fusion resulting from balanced translocation, t(X;17)(p11.2;q25), is a distinctive tumor entity. It is uncommon, and most reported cases have exclusively come from Western societies. We report a case of t(X;17)(p11.2;q25) RCC in a 6-year-old Taiwanese boy. The patient presented with dysuria and intermittent hematuria for 1 year. Nonenhanced CT showed a well-defined homogeneous hyperdensity lesion in the upper pole of the left kidney. This patient refused to receive immediate surgical procedures but had routine follow-ups. After a 9-month follow-up, the patient underwent total nephrectomy with a favorable outcome. Final diagnosis is established based on the characteristic microscopic features, strong nuclear TFE-3 immunoreactivity, and the presence of type 1 TFE3-ASPL fusion gene detected by reverse transcriptasepolymerase chain reactions. No adjuvant therapy is given, and the patient is alive without evidence of disease for 1 year and 6 months.