Diagnostic role of endoscopic ultrasonography in defining the clinical features and histopathological spectrum of gastroenteropancreatic neuroendocrine tumors

Figure 3 Photomicrographs of a neuroendocrine tumor in the pancreatic uncinate mass. A and B: Low- and intermediate-power views of the endoscopic ultrasonography-guided biopsy sample, revealing a tumor composed of epithelial cells arranged in nests and trabeculae. C: Tumor cells with monotonous round nuclei, hyperchromasia, and no significant atypia or mitoses; D: These morphological findings, along with immunohistochemical expression of the neuroendocrine marker synaptophysin, epithelial marker cytokeratin, and a Ki-67 proliferative index of < 2%, are consistent with a well-differentiated neuroendocrine tumor, World Health Organization grade I (H&E 4 ×, 10 ×, 20 × & immunohistochemistry).