NECs are poorly differentiated high-grade epithelial neoplasms, which differ from periampullary neuroendocrine tumors (NETs) by their molecular mutations, as NECs predominantly have TP53 or RB1 mutations, while MEN1, DAXX and ATRX are the entity-defining mutations for well-differentiated NETs [5]. Here, RB1 is linked to epithelial neoplasm.