Mixed exocrine-neuroendocrine intraductal papillary mucinous neoplasms of the pancreas: a case series.

We retrospectively reviewed histopathological and immunohistochemical data from patients with mixed exocrine-neuroendocrine intraductal papillary mucinous neoplasms (IPMNs) of the pancreas identified at a single centre between December 2023 and June 2026. Surgical specimens underwent detailed evaluation, including mucin profiling (MUC1, MUC2, MUC5AC) and neuroendocrine markers (synaptophysin, chromogranin A). Ten patients (median age 68.5 years, range: 31-78 years; 6 male) presented mainly with abdominal pain, weight loss, or jaundice. Most lesions were intestinal type IPMNs with focal or interspersed neuroendocrine components. Mucin expression patterns aligned with established subtype profiles, and neuroendocrine differentiation was confirmed immunohistochemically. Only one of the lesions met the World Health Organization (WHO) criteria for mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) due to the non-invasive IPMN component. This case series highlights a distinct subset of mixed non-invasive IPMN-neuroendocrine tumours not currently recognized in WHO classifications. We propose recognition of this entity to improve diagnostic precision and guide management.