Gastrointestinal neuroendocrine tumors in 2020

Table 2 Summary of different types of gastric neuroendocrine tumors

	Type I	Type II	Type III	Type IV
Distribution	70% to 80% of all GNETs	5% to 6% of all GNETs	15% to 20% of all GNETs	Most rare
Cell of origin; And location	ECL; Gastric body and fundus	ECL; Gastric body and fundus	ECL in most cases; Anywhere in stomach	Non-ECL; Anywhere in stomach
Gastrin status	Hypergastrinemia	Hypergastrinemia	Normogastrinemia	Hypergastrinemia -1/3rd of cases
Gastric mucosa	Atrophic	Hypertrophic	Normal	Atrophic most of the time but can be hypertrophic
Endoscopically	Multiple subcentimeter polypoid lesions	Multiple small (1 to 2 cm) polypoid lesions	Large (> 2 cm), solitary polypoid lesion	Large (> 4 cm) polypoid lesion
Treatment	Polypectomy, EMR, ESD, wedge resection of stomach, gastric antrectomy	Surgical resection of gastrinoma and aggressive gastrectomy	Partial or total gastrectomy and regional lymphadenectomy, chemotherapy	Partial or total gastrectomy with regional lymphadenectomy followed by adjuvant chemotherapy

ECL: Enterochromaffin-like cells; EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection; GNETs: Gastric neuroendocrine tumors.