Fig. 3
From: Composite neuroendocrine tumor and adenocarcinoma of the rectum
Immunohistochemical staining of the lesion. (Top) The neuroendocrine tumor component shows positivity for CD56, chromogranin A and synaptophysin, and is negative for carcinoembryonic antigen (CEA). The Ki-67 labeling index was low. (Middle) The adenocarcinoma component shows partial positivity for CD56, chromogranin A and synaptophysin at the periphery and positivity for CEA. The Ki-67 labeling index was 37.0%. (Bottom) The transitional zone shows positivity for CD56, chromogranin A and synaptophysin, and partial positivity for CEA. The Ki-67 labeling index was 1.6%