Table 1 WHO grading system for PNETs [27]
From: Treatment options for PNET liver metastases: a systematic review
| Grade 1 (G1) | Grade 2 (G2) | Grade 3 (G3) | |
|---|---|---|---|
| Ki-67 index | < 3% | 3–20% | > 20% |
| Mitotic count | < 2/10 HPF | 2–20/10 HPF | > 20/10 HPF |
| Differentiation | Well differentiated | Moderately differentiated | Poorly differentiated |