Increased prevalence of pancreatic neuroendocrine microadenomas in patients with intraductal papillary mucinous neoplasms: yet another example of exocrine-neuroendocrine interaction?

Introduction. Intraductal papillary mucinous neoplasms (IPMN) and neuroendocrine tumors (NET) may develop simultaneously in the pancreas. Neuroendocrine microadenomas (NMA) are precursor lesions for NET. The study aimed to determine the prevalence of NMA/NET in patients with IPMN in a series of resection specimens. Material and methods. Some 232 prospectively gathered specimens were included and examined histopathologically: 51 IPMN, 114 conventional pancreatic ductal carcinomas (PDAC) and 67 ampullary carcinomas (AMPCA). Results. NET were rare in the study samples (single cases among IPMN and AMPCA, and two cases among PDAC). In contrast, NMA were frequently found in IPMN specimens when compared to samples of PDAC and AMPCA (27.45%; 7.89%, and 7.46%, respectively, p < 0.001). Two NMA in IPMN group were related to ducts, but no case of composite (clonal) IPMN/NMA was found. Conclusions. IPMN specimens were enriched in NMA but not in NET. IPMN/NMA association may serve as a model of exocrine-neuroendocrine interaction