CD99 and neoplasm: The results demonstrated that the tumor cells were strongly positive for neuroendocrine markers, including chromogranin A (CgA) and synaptophysin (Syn), and epithelial markers cytokeratin (CK) 20, CK8/18 and epithelial membrane antigen (EMA) (Fig. 1D–H), but negative for leukocyte common antigens (LCA), thyroid transcription factor-1 (TTF-1), Melan-A, human melanoma black 45 (HMB45), vimentin (Vim), S-100, cluster of differentiation (CD)34, CD57 and CD99.