Table 2.
Classification of gastroenteropancreatic neuroendocrine tumors: Neuroendocrine neoplasms according to the World Health Organization 2019
| Terminology | Differentiation | Grade | Mitotic rate | Ki 67 index, % |
| NET, G1 | Well differentiated | Low | < 2 | < 3 |
| NET, G2 | Well differentiated | Intermediate | 2-20 | 3-20 |
| NET, G3 | Well differentiated | High | > 20 | > 20 |
| NEC, SCNEC | Poorly differentiated | High | > 20 | > 20 |
| NEC, LCNEC | Poorly differentiated | High | > 20 | > 20 |
| MiNEN | Well or poorly differentiated | Variable | Variable | Variable |
Adapted from[17]. NET: Neuroendocrine tumor; NEC: Neuroendocrine carcinoma; SCNEC: Small cell neuroendocrine carcinoma; LCNEC: Large cell neuroendocrine carcinoma; MiNEN: Mixed neuroendocrine non-neuroendocrine neoplasm.