Neuroendocrine tumours (NETs)


Type 1: Type 1 tumours (approximately 80% of total) are usually sessile polyps and associated with (usually autoimmune) atrophic gastritis, pernicious anaemia, achlorhydria and hypergastrinaemia, with the elevated gastrin being produced by gastric antral G cells.

Type 2 gastric NETs (approximately 5% of total) occur in patients with Zollinger Ellison syndrome, usually in the setting of multiple endocrine neoplasia type 1 (MEN1). They are therefore associated with gastrinomas, hypergastrinaemia and gastric hyperacidity.

Type 3 gastric NETs (approximately 15%) occur sporadically and are not associated with hypergastrinaemia

Well-differentiated neuroendocrine neoplasms (NENs)
Ki-67 index (%)Mitotic index/10 HPF
NET grade 1 (G1)< 3< 2
NET grade 2 (G2)3-202-20
NET grade 3 (G3)> 20> 20
Poorly differentiated neuroendocrine neoplasms (NENs)
Ki-67 index (%)Mitotic index/10 HPF
NEC grade 3>20>20

Goddard AF, Badreldin R, Pritchard DM on behalf of the British Society of Gastroenterology, et al The management of gastric polyps Gut 2010;59:1270-1276

Delle Fave et al. ENETS Consensus Guidelines for the Management of patients with Gastroduodenal Neoplasms. Neuroendocrinology 2012;95:74–87. DOI: 10.1159/000335595