PAX8 and neoplasm: Immunohistochemically, the tumor cells showed strong cytoplasmic expression for CK7 (Fig. 3a), S-100 (Fig. 3b), vimentin (Fig. 3c), EMA (Fig. 3d), nuclear expression for SOX10 (Fig. 3e), focal membranous for CA9 (Fig. 3f), and were negative for thyroglobulin, actin, calponin, PAX8, CD10, CK20, CDX2, CD117, DOG-1 and SMA.