Fig. 3. Immunohistochemistry of neuroendocrine component. (A) Synaptophysin (×40), (B) CD56 (×40), (C) chromogranin (×100), (D) Ki67. Neuroendocrine component is positive for synaptophysin, CD56, focal positive chromogranin, Ki67 proliferation index is 4.5%, otherwise adenocarcinoma component is negative for immunoreactivity (×400).