Histopathological classification of gastroenteropancreatic and bronchopulmonary neuroendocrine neoplasms

The gastroenteropancreatic and bronchopulmonary organ systems harbor the majority of neuroendocrine neoplasms (NENs) of the body, comprising 70% and 20% of all NENs, respectively. Their classification distinguishes between well-differentiated and poorly differentiated NENs that are associated with similarly distinctive genetic profiles. This review focuses on a comparison of the histological classification of gastroenteropancreatic NENs and bronchopulmonary NENs, with the aim of highlighting recent progress in the grading of these neoplasms and discussing the most obvious differences. Despite these differences, the principle therapeutic options are still the same for both NEN groups. Thus, further progress in genetics is needed to develop more targeted therapy strategies in future.