The differential diagnosis for PanNENs mainly include solid pseudopapillary neoplasms (SPNs), acinar cell carcinoma (ACC), MiNENs, and pancreatoblastoma58, 59, 60, 61 (Table 3). Commonly used neuroendocrine markers include synaptophysin, insulinoma-associated protein 1 (INSM1), and chromogranin, though expression of chromogranin can be focal in PanNECs. SSTR2, typically strongly expressed by PanNETs, is frequently lost in PanNECs. In addition, differentiation from a metastasis from NETs of