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Medline ® Abstract for Reference 25

of 'Surgical resection of sporadic pancreatic neuroendocrine tumors'

Classification and pathology of gastroenteropancreatic neuroendocrine neoplasms.
Klöppel G
Endocr Relat Cancer. 2011 Oct;18 Suppl 1:S1-16.
Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are composed of cells with a neuroendocrine phenotype. The old and the new WHO classifications distinguish between well-differentiated and poorly differentiated neoplasms. All well-differentiated neoplasms, regardless of whether they behave benignly or develop metastases, will be called neuroendocrine tumours (NETs), and graded G1 (Ki67<2%) or G2 (Ki67 2-20%). All poorly differentiated neoplasms will be termed neuroendocrine carcinomas (NECs) and graded G3 (Ki67>20%). To stratify the GEP-NETs and GEP-NECs regarding their prognosis, they are now further classified according to TNM-stage systems that were recently proposed by the European Neuroendocrine Tumour Society (ENETS) and the AJCC/UICC. In the light of these criteria the pathology and biology of the various NETs and NECs of the gastrointestinal tract (including the oesophagus) and the pancreas are reviewed.
Department of Pathology, Technical University of München, Ismaninger Strasse 22, 81675 München, Germany. guenter.kloeppel@alumni.uni-kiel.de