Simultaneous rectal neuroendocrine tumors and pituitary adenoma: A case report and review of literature

Figure 3 Hematoxylin-eosin staining and immunohistochemical staining. A and B: Hematoxylin-eosin staining shows the pathological features of rectal neuroendocrine tumors in the larger and smaller tumor tissue specimens (20 ×); C-E: Immunohistochemical staining of neuroendocrine markers CD56, Syn, and CgA in representative tumor tissue selected by the physician (4 ×); F: Ki-67 expression in the neuroendocrine tumor at the rectum by immunohistochemistry (10 ×). Brown nuclear stain highlights Ki-67-positive tumor cells.