Clinical experience sharing on gastric microneuroendocrine tumors: A case report

Table 1 Classification of gastric neuroendocrine neoplasms on the basis of the 2016 European Neuroendocrine Tumor Society guidelines

	Type 1	Type 2	Type 3
Proportion among G-NENs, %	70-80	5-6	14-25
Tumor characteristics	Often small (< 1-2 cm), multiple in 65% of cases, polypoid in 78% of cases	Often small (< 1-2 cm) and multiple, polypoid	Unique, often large (> 2 cm) polypoid and ulcerated
Associated conditions	Atrophic body, gastritis	Gastrinoma/MEN-1	None
Pathology	NET G1-G2	NET G1-G2	NET G3
Serum gastrin levels	↑	↑	Normal
Gastric pH	↑	↓	Normal
Metastases, %	2-5	10-30	50-100
Tumor-related deaths, %	0	< 10	25-30

G-NENs: Gastric neuroendocrine tumors; NET: Neuroendocrine tumor; MEN-1: Multiple endocrine neoplasia type 1.