PAX8 and renal cell carcinoma: 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.