Does X mark the spot? A case series of discrepant preoperative insulinoma localization.

Summary: We explored the challenges associated with the localization of insulinomas, pancreatic neuroendocrine tumors responsible for hypoglycemia. Insulinomas often present with varied symptoms, leading to potential diagnostic delays. While biochemical evidence confirms the presence of insulinomas, precise preoperative localization remains challenging despite advanced imaging techniques. Our study highlights contradictory findings between intra-arterial calcium stimulation tests and 68Ga-NODAGA-Exendin-4-PET/CT in two cases of insulinoma where conventional imaging studies did not reveal the location. We demonstrate that in these cases, surgical exploration resolved the discrepancies and led to a resolution of the disease. Our results also suggest a potential need to revise the threshold for intra-arterial calcium stimulation tests to enhance diagnostic accuracy. This short report emphasizes the complexity of insulinoma localization and the necessity for integrating multiple diagnostic approaches to achieve optimal patient care. Learning points: Diagnosis of insulinoma can be delayed and complicated by unspecific symptoms and difficulties in the localization techniques. There are different methods for preoperative insulinoma localization which may render conflicting results. When conventional imaging studies do not reveal the location and advanced imaging techniques and metabolic tests show discrepant results, surgical exploration may resolve the discrepancies and lead to a resolution of the disease. It is necessary to integrate multiple diagnostic approaches to achieve optimal patient care.