Neuroendocrine tumours in rare sites: Differences in nomenclature and diagnostics - A rare and ubiquitous histotype

The diagnosis of neuroendocrine tumours in typical sites, as gastrointestinal tract and lung, is based upon wellcoded criteria that have become familiar to most of the pathologists. Much more difficult is the recognition and allocation of proper nomenclature to be referred to the same histotype in locations where these tumours have a lower incidence. The aim of our review was to provide a quick handbook of the main diagnostic pitfalls known in literature that can interpose in the histopathological examination of neuroendocrine tumours in rare sites (urinary system and male genital organs, female genital organs, head and neck and breast).