Neuroendocrine neoplasms (NEN) represent a rare and heterogeneous group of malignancies, whose incidence is increasing trough the last decades, both because of better detection strategies and of a growing awareness. The aim of biochemical, radiological, and nuclear medicine improved techniques is to early identify and characterize these tumors, in order to offer new and tailored treatments. An updated overview of diagnosis, classification, and treatments in patients with NEN is provided, with the aim to summarize recent evidence in the field of NEN. Interesting novelties in pathological examination with new immunohistochemical panels, radiological and functional imaging techniques, as well as the latest published guidelines in NEN are discussed, with focus on therapeutic strategies according to primary. This concise but thorough examination of the current advancements in NEN aims to represent a useful tool for clinicians and researchers working in this field. NEN classification and characterization have changed trough years, aiming to obtain a precise tumor profile and the best therapeutic strategy. NEN diagnosis and treatment should be discussed by expert multidisciplinary group to improve management and survival rates.