Diabetes mellitus as an early symptom of pancreatic cancer diagnosed three years later.

We present a case of a 40-year-old man with strong family history of diabetes. His pancreatic ultrasonography was normal at the discovery of his diabetes. Anti-pancreatic antibodies were negative. The patient was treated by insulin and continued to loose weight. His diabetes remained unstable during the follow-up. Three years later, a pancreatic adenocarcinoma was diagnosed which was locally advanced and could not be removed surgically. This observation argues among several mechanisms explaining diabetes in subjects with pancreatic cancer, in favor of tumor-derived diabetogenic substance and suggests that diabetes mellitus could reveal pancreatic cancer even in the presence of conventional risk factors of type 2 diabetes.