Last decade of advances in gastric neuroendocrine tumors: Innovations, challenges, and future directions

Table 1 It provides an overview of the basic differences between gastric neuroendocrine tumors type I, II, III, and IV features

	Type I	Type II	Type III	Type IV
Prevalence (%)	70-80	5-7	10-20	Rare
Predominance	Females	Same frequency male:female	Males	Not determined (possibly male)
Background	Chronic autoimmune gastritis	Zollinger-Ellison Syndrome (gastrinomas)	Normal gastric mucosa	Hypergastrinemia (1/3 of cases). Chronic atrophic gastritis (82% of cases)
Number of lesions	Multiple	Multiple	Single	Single
Size of lesions	1-2 cm	< 10 mm	> 2 cm	> 4 cm (usually)
Site of lesions	Gastric body/fundus	Gastric body/fundus	Gastric body/fundus	Any part of the stomach
Underlying mucosa	Atrophic	Hypertrophic	Normal	Mainly atrophic (less frequently hypertrophic)
Cell of origin	ECL	ECL	ECL	Non-ECL
Serum gastrin levels	Elevated	Elevated	Normal	Elevated or normal
Gastric pH	High (> 7)	Low (< 2)	Normal	Approaching neutral to slightly alkaline
Aggressiveness	Low	Greater	High	High
Invasion	Rare	More common	Common	Common
Prognosis	Excellent	Very good	Poor	Poor

ECL: Enterochromaffin-like.