logo logo
Search: Organ site Search: Tumor / Syndrome
or
WHO Classification of Tumours
Neuroendocrine tumor G1 (NET G1) / Carcinoid
Pancreas


Definition

Pancreatic NETs and NECs (neuroendocrine carcinomas) are classified on the basis of criteria similar to those for other neuroendocrine neoplasms of the gastrointestinal tract as below:

A neuroendocrine tumour (NET) is defined as a well-differentiated, neuroendocrine neoplasm composed of cells with features similar to those of the normal gut endocrine cell, expressing general markers of neuroendocrine differentiation (usually diffuse and intense chromogranin A and synaptophysin) and hormones (usually intense but not necessarily diffuse) according to site, with mild- to-moderate nuclear atypia and a low number of mitoses.
The proposed grading based on proliferation with the following definitions of mitotic count and Ki67 index:
– G1 (NET G1): mitotic count, <2 per 10 high power fields (HPF) and/or ≤2% Ki67 index;
G2 (NET G2) : mitotic count 2–20 per 10 HPF and/or 3–20% Ki67 index

Click for details
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
4th Edition
International Agency for Research on Cancer: Lyon 2010



.

Commentary: Neuroendocrine tumours of the digestive system

Pancreatic NETs can be associated with characteristic clinical syndromes owing to hormone hypersecretion (“functioning NETs” or “syndromic NETs”) or they can be nonfunctioning (“nonsyndromic NETs”. Although routine immunohistochemical staining for peptide hormones is not suggested for clinically nonfunctional pancreatic NETs, for cases in which the production of a specific hormone has been demonstrated in the majority of the neoplastic cells, it is acceptable to supplement the diagnosis of pancreatic NET to reflect the corresponding cell type (e.g. “α cell/glucagon-producing NET,” “β cell/insulin-producing NET,” “G cell/gastrin- producing NET”), but specific functional terms (e.g. “glucagonoma,” “insulinoma,” “gastrinoma”) should not be used in the absence of a hormonal syndrome. Changes to the classification of pancreatic neuroendocrine neoplasms since the third edition of the WHO Classification of Tumours include the use of “neuroendocrine” rather than “endocrine” (to parallel the terminology of the remainder of the gastrointestinal tract) and the replacement of the hybrid grade- and stage-based classification system with a purely grade-based system determined by proliferative rate. Pancreatic NETs should also now be staged, since stage is an independent prognostic indicator

Click for details
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
4th Edition
International Agency for Research on Cancer: Lyon 2010



.