Management of early gastrointestinal neuroendocrine neoplasms

Table 3 Clinicopathological characteristics of gastric neuroendocrine neoplasms[4,23-26]

Gastric NETs/carcinoids				Gastric NECs (poorlydifferentiated NENs)
	Type 1	Type 2	Type 3	Type 4
Relative frequency	70%-80%	5%-6%	14%-25%	6%-8%
Features	Mostly small (< 1-2 cm) and multiple	Mostly small (< 1-2 cm) and multiple	Solitary often > 2 cm	Solitary mostly exulcerated, > 2 cm
Associated conditions	CAG	MEN1/ZES	No	No
Histology	Well differentiated G1	Well differentiated G1	Well/moderate differentiated* G2a	Poorly differentiated G3
Serum gastrin	(Very) high	(Very) high	Normal	(Mostly) normal
Gastric pH	Anacidic	Hyperacidic	Normal	(Mostly) normal
Metastases	< 10%	10%-30%	50%-100%	80%-100%
Tumor-related deaths	no	< 10%	25%-30%	≥ 50%

NET: Neuroendocrine tumor; NEC: Neuroendocrine carcinoma; CAG: Chronic atrophic gastritis, due to pernicious anemia or Helicobacter pylori infection; MEN1: Multiple endocrine neoplasia type1; ZES: Zollinger-Ellison syndrome; MEN1/ZES: ZES associated with MEN1; G1-3 histological differentiation: see Table 2; ENETS and NANETS nomenclature are identical for G1 and G3 grading: G1: Well differentiated; G3: Poorly differentiated. For G2 grading ENETS and NANETS nomenclature differ: *ENETS-nomenclature: G2: Well-differentiated;

^aNANETS-nomenclature: G2: Moderate differentiated (modified from Scherübl et al[13])