Diabetes Mellitus-Not Just Type 1 or Type 2 Anymore

Diabetes mellitus traditionally has been categorized as type 1 (insulin deficiency due to autoimmune destruction of islet cells) or type 2 (insulin resistance with the development of relative insulin deficiency). However, other pathophysiologic etiologies for diabetes must be considered in the evaluation of patients with new-onset diabetes.

We report the case of a 50-year-old man with a diagnosis of type 2 diabetes mellitus who-despite appropriate pharmacotherapy-developed worsening hyperglycemia. Further investigation revealed the presence of metastatic pancreatic cancer.

Although an association between pancreatic cancer and diabetes has been noted widely in the gastroenterology, oncology, and endocrine literature, a paucity of primary care literature on the topic exists. Features of predominant insulin deficiency and new onset of diabetes in a patient without family history of type 2 diabetes should raise suspicion for undetected/early-stage pancreatic cancer.

This case highlights the importance of considering all possible pathophysiologic etiologies when a patient has a new diagnosis of diabetes. Clinicians should consider the possibility of pancreatic cancer in patients with new-onset diabetes mellitus, especially when features not characteristic of type 2 diabetes are present. Understanding the relationship between diabetes and pancreatic cancer has the potential to improve early detection of pancreatic cancer and can provide an opportunity for early treatment and improved survival.