General Pathology of Neuroendocrine Growths GI Tract

Neuroendocrine cells of the gut may generate hyperplastic, dysplastic and neoplastic growths. Hyperplastic and dysplastic lesions are well known and classified in the stomach and the duodenum. The World Health Organization classifies the neuroendocrine neoplasms as Neuroendocrine Tumors (NET) when of low to intermediate grade (G1–G2) and Neuroendocrine Carcinomas (NEC) when of high grade (G3), according to a three tier grading system based on Ki67 staining and mitotic index. For each anatomical region of the gut a specific staging systems for neuroendocrine neoplasms is provided. The prognosis of neuroendocrine cancer patients correlates with cancer grade and stage. Neuroendocrine cell-type specific tumor subtypes are described.