The endocrine cells of the pancreas and their related cells throughout the gastrointestinal tract give rise to a variety of tumors that pose a diagnostic challenge. There has been progress in understanding their histogenesis, morphology, immunohistochemistry, molecular biology and classifications. This review will focus on nomenclature/terminology, classification, the role of immunohistochemistry, molecular advances, including genetic predisposition, and potential therapeutic targets to define the role of pathology in the application of prognostic and predictive markers for this disease.
