Tumors arising from the diffuse neuroendocrine (NE) system are mostly located in gastro-entero-pancreatic (GEP) tract and in the lung, and show increasing incidence and wide spectrum appearance. Different therapeutic possibilities need accurate diagnosis, classification and prognosis prediction, which determination for pathological diagnostics is a great challenge. All of these are based on the WHO classification, TNM classification of tumors of different location, and clinicopathological characterization. This review provides a comprehensive overview of the general characteristics of NE tumors, in particular the clinical-pathological properties of gastro-entero-pancreatic tumors and the requirements of correct pathological diagnosis for treatment
