Although none of the TFE3-rearranged PEComas in the initial study occurred in the kidney, 35 of such tumors have since been found in this organ, making it the most frequent site for this neoplasm [39,42,76,77,78,79,80,81,82,83] (Figure 5A). The gene discussed is TFE3; the disease is neoplasm with perivascular epithelioid cell differentiation.