MiT family translocation-associated (TFE3 positive) renal cell carcinoma of childhood

Translocation‐associated renal cell carcinoma (t‐RCC) is a group of uncommon tumors, which are characterized by recurrent gene rearrangements of TFE3 and transcription factor EB (TFEB) loci and have two distinct subtypes, namely, Xp11‐ and t(6;11) t‐RCC, respectively.[1] Both TFE3 and TFEB loci belong to microphthalmia transcription factor (MiT) family, therefore, in the recent 2016 classification of the World Health Organization, these tumors are now categorized as MiT family translocation‐associated RCC (MiT‐RCC).[2] Out of these two types of t‐RCC, Xp11 t‐RCC involve TFE3 gene, which commonly fuses to PRCC and ASPL loci on chromosomes 1q21 and 17q25, respectively.[1] These fusions produce overexpression of TFE3 protein, which can be immunohistochemically demonstrated in the nuclei of tumor cells.[3] We herein report a case of TFE3‐positive Xp11 t‐RCC in a child.