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WHO Classification of Tumours
Neuroendocrine tumor G1 (NET G1) / Carcinoid
Esophagus


Definition

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 220 per 10 HPF and/or 320% Ki67 index

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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



.

In the esophagus, neuroendocrine tumours (NETs) are exceedingly rare. Most of the reported cases are neuroendocrine carcinomas (NEC) or mixed adenoneuroendocrine carcinoma (MANEC) , the latter with either an adenocarcinoma or a squamous cell carcinoma component

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



. They are often large and located in the lower part of the oesophagus.

Commentary: Neuroendocrine tumours of the digestive system