PMEL and clear cell renal carcinoma: In addition, PEComa is readily differentiated from epithelioid extra-GIST and metastatic clear-cell renal cell carcinoma by positive immunohistochemical staining for Melan-A and HMB-45 and negative staining for both CD117, Dog-1, CD34 and pan-cytokeratin (AE1/AE3).