Table 1.
Current pathological classification of UKP-, GUGy- and HN-NENs and corresponding IARC–WHO 2018 consensus classification14,68,106, 107, 108
| Common classification for UKP-, HN- and GUGy-NENs used in these guidelines14 | HN-NEN classification108 | GU-NEN classification106 | Gy-NEN classification107 |
|---|---|---|---|
| NET | |||
| G1 NET | G1 NET or middle-ear NET | Well-differentiated NET (no grading) | G1 NET (Ovary: carcinoid tumour, no grading) |
| G2 NET | G2 NET or middle-ear NET | G2 NET | |
| G3 NET | No G3 NET in the classification | No G3 NET in the classification | |
| NEC | |||
| Small-cell NEC | Small-cell NEC | Small-cell NEC | Small-cell NEC |
| Large-cell NEC | Large-cell NEC | Large-cell NEC | Large-cell NEC |
| MiNEN | Mixed NENs | Carcinoma admixed with NEC | |
G, grade; GU, genitourinary; GUGy, genitourinary or gynaecological; Gy, gynaecological; HN, head and neck; IARC, International Agency for Research on Cancer; MiNEN, mixed neuroendocrine–non-neuroendocrine neoplasm; NA, not applicable; NEC, neuroendocrine carcinoma; NEN, neuroendocrine neoplasm; NET, neuroendocrine tumour; UKP, unknown primary; WHO, World Health Organization.