KRT20 and sarcomatoid carcinoma: As other immunohistochemical markers were negative, including CD45, CD163, CD68, Desmin, Myogenin, Melanoma, S100, α-SMA, Cytokeratin 7, Cytokeratin 20, MDM2 and CDK4 (Table 1), the tumors were diagnosed as sarcomatoid carcinomas.