Two Cases of Mixed Neuroendocrine Non-neuroendcrine Cell Neoplasms (MiNENs) of the Pancreas with Notable Molecular Pathological Features

We herein report two cases of pancreatic mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs). Case A was a mixed ductal-neuroendocrine cell carcinoma with a KRAS mutation and loss of RB1 and SMAD4 expression. Case B was a mixed acinar-neuroendocrine cell carcinoma with wild-type KRAS and loss of p16 and SMAD4 expression. The expression of RB1 and ARID1A was also reduced. These results support the recently proposed classification of neuroendocrine carcinoma into ductal and acinar types based on molecular features, which may facilitate the understanding and development of specific treatments for this intractable tumor.