In these challenging cases, PAX8 (positive in TFE3-rearranged renal cell carcinoma and negative in pure epithelioid PEComa, Figure 3D) and CD68 (PG-M1) (negative in TFE3-rearranged renal cell carcinoma and positive in pure epithelioid PEComa) are useful markers to reach the proper diagnosis. The gene discussed is TFE3; the disease is hereditary clear cell renal cell carcinoma.