Figure 2.

Photomicrographs of histological and immunohistochemical findings. Nests containing biphasic cell populations within dense connective tissue are shown. The presence of small neuroblast-like cells with delicate fibrils between them (indicated by dashed arrows) and large melanin-containing cells (indicated by arrows) were observed (H&E, magnification ×400) (a). Large epithelial-like cells were positive for cytokeratin AE1/AE2 (b) (magnification ×100), epithelial membrane—EMA (c) (magnification ×400), and HMB45 (d) (magnification ×100). Both cell types were positive for vimentin, but the signal intensity was stronger in large cells (e). Both cell types were also positive for chromogranin, but the signal intensity was stronger in small cells (f) (magnification ×100). Synaptophysin was expressed by small neuroblast-like cells (magnification ×100) (g). Nuclear expression of Ki67 was also observed (magnification ×100) (h).