Gastric neuroendocrine tumors: A review of pathology and updated roadmap to surgical management

Table 1 Characteristics of gastric neuroendocrine tumors subtypes

	Type I (75%-80%)	Type II (5%)	Type III (15%-25%)
Gastrin levels	High gastrin	High gastrin	Normal gastrin
Gastric acid	pH > 4, hypo- or achlorhydria	pH < 2, hyperchlorhydria	pH < 4, normal gastric HCL
Surrounding gastric mucosa	Atrophic gastritis	Corpus mucosal hypertrophy	Normal mucosa
Underlying cause	Autoimmune atrophic gastritis	Gastrinoma related to Zollinger-Ellison, MEN-1 syndrome	Sporadic mutations
Tumor number	Multifocal	Multifocal	Singular
Tumor size	Smaller, < 2 cm	Smaller, < 2 cm	Larger, > 2 cm
WHO grade	1-2	1-2	1-3
Ki-67%	Lower	Lower	Higher
Malignancy potential	Low	Low	High

This table compares qualities between type I, II, and III G-NETs, as their characteristic behavior, presentation, and management differ. MEN-1: Multiple endocrine neoplasia type 1; WHO: World Health Organization.