CEACAM5 and neuroendocrine neoplasm: Immunohistochemistry of the excisions displayed typical characteristics of neuroendocrine tumors that were positive for synaptophysin (Syn), CD56, Ki67 (5%), and P63; and negative for chromogranin A (CgA), neuron-specific enolase (NSE), and carcinoembryonic antigen (M-CEA).