Immunohistochemistry (IHC) showed tumor cells diffusely expressed TFE3, and fluorescence <i>in situ</i> hybridization (FISH) demonstrated disruption of the TFE3 locus, confirming the diagnosis of Xp11.2 tRCC, the most common subtype of MiTF tRCC. The gene discussed is MITF; the disease is neoplasm.