MON-636 Growth of Pancreatic Heterotopic Tissue: A Rare Adverse Effect of Semaglutide

Abstract Disclosure: A. Barsegian: None. M. Kinaan: None. Background: Pancreatic heterotopia, the presence of pancreatic tissue outside its usual anatomical location, is rare with a prevalence of approximately 0.18% based on a large clinicopathological study of 99,544 surgical resections and upper endoscopic biopsies. Among these cases, the small intestine is a common site, accounting for 26% of the occurrences. We present a case of a patient who had undiagnosed pancreatic heterotopia in the small intestine that was unmasked by the use of semaglutide. Case Presentation: A 47-year-old female with a history of type 2 diabetes mellitus presented to our endocrine clinic for diabetes management. She was on metformin ER 500mg and glimepiride 4mg twice daily with inadequate control (HbA1C of 8.5%). We stopped glimepiride and advised her to start semaglutide. She had no pre-existing pancreatic disease at that time. She titrated semaglutide to a dose of 1mg weekly over the course of 8 months and achieved HbA1C of 6.9%. The patient was tolerating the medication well for several months. After 1 year of semaglutide use, she started developing subacute abdominal pain. CT imaging revealed an intestinal mass causing small bowel obstruction. She underwent surgical resection. Postoperative pathology revealed benign pancreatic heterotopia embedded in the wall of the small intestine. Based on these findings, we decided to stop semaglutide due to its possible growth stimulating effect on pancreatic tissue. Discussion: The effect of GLP-1 receptor agonists on pancreatic heterotopia is not documented in medical literature. However, there is evidence that GLP-1 receptor agonists are associated with an increase in pancreatic mass in general due to acinar cell hypertrophy. Therefore, we hypothesize that the use of semaglutide in this patient caused growth of the dormant heterotopic pancreatic tissue in the intestine. This is the first case report in literature linking use of semaglutide, or any GLP-1 receptor agonist, to growth of pancreatic heterotopic tissue. Conclusion: Clinicians should be vigilant about the potential effects of GLP-1 RAs on pancreatic tissue. In patients with known anatomic pancreatic abnormalities, such as pancreatic heterotopia, careful consideration and individualized treatment strategies are essential to balancing glycemic control and safety. Presentation: Monday, July 14, 2025