Biological characteristics of pediatric renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions

PurposeTo investigate the clinical features of pediatric Xp11.2 translocation renal cell carcinoma (RCC).MethodsA retrospective review of 22 cases over 35 years.ResultsXp11.2 translocation RCCs were identified in 13 boys and 9 girls with a median age of 10.5 years (range: 2.5–16 years). RCC presented with hematuria in 17, abdominal mass in 1, abdominal masses with hematuria in 2, abdominal pain with hematuria in 1, and as an incidental finding in 1 patient. Ten patients were classified stage I, 10 were stage III, and two were stage IV. Of the 10 patients with stage I RCCs, 3 patients with tumor measuring less than 7 cm had nephron-sparing surgery (NSS) and 17 patients underwent simple nephrectomy. A 15-cm tumor was incompletely removed in one patient and another patient with a 25-cm × 18-cm × 15-cm tumor had gross residual. Of the 15 patients followed up between 6 months and 35 years, 13 were still living and 2 had died after surgery.ConclusionsXp11.2 translocation RCC is the predominant form of pediatric RCC, associated with advanced stage at presentation. Nephrectomy is the usual treatment for RCC but NSS is an option for patients with tumors measuring < 7 cm. Patients with N + M0 maintained a favorable prognosis following surgery alone.