Table 1.
Minimum and optional requirements for a pathology report of gastroenteropancreatic neuroendocrine neoplasm [adapted from Volante et al. (87)].
| Minimum Requirements | WHO used (2017-2019) for pathology report |
| Differentiation and WHO tumor type (NET, NEC, MINEN), if NEC large or small cell, if MINEN, histotype of NE and non-NE components | |
| Tumor Grade (<3% for G1, 3-20% G2, > 20% G3) for NET | |
| Ki-67 index as precise value (%) | |
| Size and location | |
| Depth of invasion | |
| Lympho-vascular invasion (present/absent) | |
| Perineural invasion (present/absent) | |
| Lymph node status (number evaluated nodes, number of positive nodes) | |
| R status and description of margins | |
| Immunohistochemical markers used for identification of primary, in case of biopsy | |
| Immunohistochemical markers performed and relative results | |
| pTNM stage (AJCC/WHO/UICC) | |
| Optional Requirements | Ki-67% on different site (primary and metastases) |
| Mitotic index as value (x2 mm2) | |
| If positive lymph node, description of presence/absence of extra nodal extension | |
| Hormone positivity on immunohistochemistry | |
| Somatostatin receptor immunohistochemistry (not for routine patology report) |
NET, neuroendocrine tumor; NEC, neuroendocrine carcinoma; MINEN, mixed neuroendocrine-non-neuroendocrine neoplasms; AJCC, American Joint Commission on Cancer; WHO, World Health Organization; UICC, Union for International Cancer Control.