Figure 3

Photomicrographs showing representative immunohistochemistry. (A, B, and C) Epithelioid cells showed positive reactivity for synaptophysin, somatostatin, and CD56 (× 400). (D) Spindle-shaped cells showed positive reactivity for S-100 protein (× 400). (E) Tumor cells of both types showed negative reactivity for chromogranin A (× 400). (F) Tumor cells invade into the lymphatic lumen (immunohistochemistry with podoplanin (D2-40) antibody, × 400). (G) Epithelioid cells metastasizing at the lymph node showed positive reactivity for synaptophysin (× 400). (H) No spindle-shaped cells were found in the metastatic focus as confirmed by the lack of S-100 protein-positive cells (× 400).