Table 1.
ENETS/WHO nomenclature and classification of GEP-NENs [12]
| Well-differentiated (low-grade, G1) | Well-differentiated (intermediate-grade, G2) | Poorly differentiated (high-grade, G3) small, large-cell | |
|---|---|---|---|
| Appearance | monomorphic population of small, round cells | 1 | cellular pleomorphism |
| Mitotic rate | <2 | 2–20 | >20 |
| Ki-67 inde* | ≤2% | 3–20% | >20% |
| Necrosis | absent | 1 | present |
| Prognosis | prolonged survival | intermediate | poor |
1
Applies only to the WHO and the European Neuroendocrine Tumor Society (ENETS) classification of GEP-NENs.
*
Not well defined in the medical literature.