Pancreatic cancer represents one of the most aggressive types of cancer, resulting in a late diagnosis and rapid death (poor overall survival). After adenocarcinoma (counting almost 80% of cases of pancreatic cancer), the second category, as frequency, is represented by the family of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Pancreatic cancer is characterized by genetic heterogeneity and may results in different evolution among metastases, which may acquire driver mutations with the ability to transform under the action of several cancer treatments. Here we report a case of a 64-year-old patient diagnosed with pancreatic tumor localized on the body and tail, invasive in the splenic and portal vein, pT3pN0M0 (adenocarcinoma pancreatic cancer), treated with a multimodal approach: surgery (splenectomy and distal pancreatectomy, with suture of the portal vein), chemotherapy, in 2010, that relapsed in 2015, with local recurrence that was resected and distant liver metastases. Immunohistochemistry of the recurrence tumor showed a neuroendocrine transformation of the tumor, with major implications in treatment and prognosis. Computed tomography examination, as well as histopathological and immunohistochemically testing, sustained positive and differential diagnosis.