“…The tumor cells in both cases showed negative reactivity for melanoma-specific antigen HMB-45, neuron-specific enolase (NSE 1:50, Dako, Kyoto, Japan) for detecting neuronal differentiation, glial fibrillary acidic protein (GFAP, 1:50, Dako) for detecting glial differentiation, alpha-smooth muscle actin (1:50, Dako) for muscle differentiation. They were positive for S-100 protein (1:2000, Dako) and vimentin (1:50, Dako), which provided support for their origin from the NPCE [1]. They were also positive for cytokeratin KL-1(KL-1, 1:100, Immunotech, Marseilles, France) and cytokeratin CAM 5.2, which are monoclonal antibodies to a large spectrum of cytokeratins.…”