Intraductal papillary mucinous neoplasm worsening glycemic control in a patient with type 2 diabetes mellitus.

Intraductal papillary mucinous neoplasm (IPMN) is a rare precancerous pancreatic tumor that accounts for about 1% of pancreatic neoplasms and can impair both exocrine and endocrine function. We present the case of a woman with long-standing type 2 diabetes mellitus who developed worsening glycemic control due to pancreatic IPMN and its pathogenesis. Laboratory evaluation revealed evidence of severe pancreatic exocrine insufficiency, while imaging demonstrated a ductal lesion consistent with IPMN. Endoscopic ultrasound with biopsy confirmed a main-duct IPMN, and the patient subsequently underwent pancreaticoduodenectomy, with pathology demonstrating low-grade disease without invasion. This case highlights the connection between pancreatic structural disease and glucose metabolism. Progressive ductal obstruction and parenchymal injury from IPMN can result in combined endocrine and exocrine dysfunction, manifesting as pancreatogenic (type 3c) diabetes and malabsorption. Early recognition is critical, as it enables timely diagnostic evaluation, appropriate surgical management, and optimization of metabolic and nutritional status. Additionally, this case underscores the need for individualized diabetes management in the setting of pancreatic insufficiency and highlights ongoing uncertainties regarding the safety of certain glucose-lowering therapies in patients with premalignant pancreatic lesions.