Belgian guidelines for pathology reporting of neuroendocrine neoplasms of the pancreaticobiliary and gastrointestinal tract.

Since neuroendocrine neoplasms are rare tumors, registration of patient data in national and multinational registries is recommended. Indeed, this will facilitate multicenter studies on the epidemiology, efficacy and safety of diagnostic and therapeutic strategies for well-differentiated neuroendocrine tumors as well as for neuroendocrine carcinomas. In Belgium, data on patient and tumor characteristics of all newly diagnosed malignancies have been collected in the Belgian Cancer Registry since 2004 including anonymized full pathological reports. The Digestive Neuroendocrine Tumor (DNET) registry collects information on classification, staging, diagnostic tools and treatment in a prospective national online database. However, the terminology, classification and staging systems of neuroendocrine neoplasms have changed repeatedly over the past 20 years as a result of a better understanding of these rare tumors, by joining forces internationally. These frequent changes make it very difficult to exchange data or perform retrospective analyses. For optimal decision making, for a clear understanding and to allow reclassification according to the latest staging system, several items need to be described in the pathology report. This paper provides an overview of the essential items in reporting neuroendocrine neoplasms of the pancreaticobiliary and gastrointestinal tract.