Neuroendocrine tumours of the pancreas: recent developments in staging and grading

A new classification of digestive neuroendocrine neoplasms, including pancreas, has been formulated in the 2010 revision of the WHO classification of tumours of the digestive system. The terminology and principles of this novel classification are different from those used previously. Three main grading categories are recognized (neuroendocrine tumour G1, neuroendocrine tumour G2 and neuroendocrine carcinoma of small and of large cell types) combined with a site-specific TNM staging, which was published in 2009 by the AJCC-UICC following a 2006 TNM proposal by the European Neuroendocrine Tumor Society.This review describes the different classifications that have been used in the last 10 years, in order to better understand the sequential modifications which have been progressively added. It highlights problems of terminology that could lead to confusion and also gives some recommendations for the formulation of pathological reports.