Current Concepts on Gastric Carcinoid Tumors

Table 1

WHO 2010 classification of NEN/NETs.

	Grade 1	Grade 2	Grade 3*
Metastases	−	−	+
Muscularis propria invasion	−	±	+
Tumor size (cm)	≤2	>2	Any
Mitoses/10 HPF**	<2	2–20	>20
Ki 67 index %	≤2	3–20	>20
Angio-invasion	Never	Late	Always

∗Grade 3 are divided into small cell and large cell neoplasms.
∗∗HPF: high-power fields.