DES and neoplasm: EIMS share the following common characteristics (2): (i) epithelioid tumor cells with round nuclei; (ii) myxoid stroma with inflammatory infiltrates; (iii) ALK positivity with a nuclear membrane or perinuclear staining pattern; (iv) desmin positive immunostaining in the cytoplasm of the tumor cells; and (v) the frequent presence of RANBP2-ALK fusion gene.