Intraductal papillary mucinous neoplasm unveiling incidental multifocal pancreatic neuroendocrine tumors: a challenging case report.

Introduction and importance: The synchronous occurrence of multifocal pancreatic neuroendocrine tumors (NETs) with an intraductal papillary mucinous neoplasm (IPMN) is exceedingly rare, with limited cases documented. The biological relationship between these dual pathologies remains poorly understood. Case presentation: A 36-year-old man presented with epigastric pain. Imaging revealed a segmental cystic dilatation of the main pancreatic duct, consistent with an IPMN, but no discrete mass. Following left pancreatectomy, histopathological examination identified a low-grade pancreatobiliary-type IPMN alongside an unpredicted well-differentiated, grade 1, pancreatic NET and multiple microscopic neuroendocrine microtumors. Immunohistochemistry confirmed neuroendocrine differentiation. The postoperative course was uneventful. Clinical discussion: The coexistence of IPMN and NET is exceptionally rare, and its pathogenesis remains unclear. Their simultaneous presence in the same pancreatic region suggests a potential biological link rather than coincidence, possibly through shared genetic or microenvironmental factors. This case, involving a younger patient, raises important questions about the clinical behavior of multifocal neuroendocrine microtumors and the implications for surveillance. Comprehensive histological evaluation remains critical, particularly when imaging fails to detect small or multifocal lesions. Conclusion: This case underscores the importance of meticulous pathological examination in identifying synchronous lesions in IPMN cases. It highlights the need for further research to explore the mechanisms underlying this rare association and to establish standardized guidelines for diagnosis, treatment, and long-term management.