Incidence of Gastrointestinal Neuroendocrine Tumor: Case Series, Armed Forces Hospital Southern Region, Hospital-Based Tumor Board Registry

Figure 3

Histopathology features of one of the cases, well-differentiated neuroendocrine tumor of the small intestine (ileum), classic type: (a–c) the histological sections show tumor cells with minimal pleomorphism arranged in cording and nesting growth patterns, extensively involving the mucosa, submucosa, and muscle layer. The main bulk of the tumor is seen in the submucosa and the muscle layer. The tumor cells have stippled chromatin, inconspicuous nucleoli, and slightly granular eosinophilic cytoplasm. There is no significant mitotic activity, and the tumor cells show little pleomorphism. There is no cell necrosis (H&E stains: (a) ×4, (b) ×10, (c) ×20, and (d) ×40). The tumor cells were positive for the epithelial markers CDX-2 ((e) ×10) and pancytokeratin ((f) ×10) and negative for CK7 ((g) ×10) and CK20 ((h) ×10). The tumor cells were diffusely and strongly reactive for the markers of neuroendocrine differentiation including both synaptophysin ((i) ×40) and chromogranin ((j) ×4 and (k) ×10). Ki67 labelling index was very low (less than 1%, (l) ×10).

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)

(k)

(l)