Interestingly, patient’s left kidney showed, besides PLNRs, some cystic lesions characterized by an epithelium reactive for TFE3, which is a marker for a specific RCC subtype, primarily occurring in children and young adults and characterized by Xp11.2 translocations leading to different type of TFE3 gene fusions13. The gene discussed is TFE3; the disease is renal cell carcinoma.