Endocrine Abstracts

JOINT2113

Introduction: Insulinomas are rare, typically benign neuroendocrine tumors of the pancreas that cause hypoglycemia due to excessive insulin secretion. Malignancy can occur, particularly with local invasion or metastasis. These tumors are often associated with Multiple Endocrine Neoplasia type 1 (MEN 1), a genetic syndrome that predisposes individuals to various endocrine tumors. This work presents the experience of our department with a series of 12 insulinoma cases over a 22-year period, from 2003 to 2025.

Methods and results: The cohort consisted of 11 females and 1 male, yielding a female:male ratio of 11:1, with a median age at diagnosis of 38.58 years (range: 10–69 years). The diagnosis was confirmed through biochemical testing, such as measuring fasting plasma glucose, insulin and C-peptide levels, with a documented hypoglycemic episode in all patients. The tumors were localized using CT or MRI in 11 cases (91.7%), with intraoperative echographic exploration in one (8.3%). All patients underwent surgery, except for one who refused and is currently being treated with somatostatin analogs. The most common localization of insulinomas was in the pancreatic tail (58.3%), followed by the pancreatic head (25%), and multiple localizations in MEN 1 syndrome (16.7%). The benign insulinomas comprised 9 lesions (75%), with 7 classified as NET-G1 (58.3%) and 2 as NET-G2 (16.7%), both occurring in the context of MEN 1 syndrome. Three patients experienced recurrent hypoglycemic symptoms following surgery: one was lost to follow-up, while the other two, diagnosed with MEN 1 syndrome, are being managed with somatostatin analogs and diazoxide. It is important to note that, within the MEN 1 syndrome group, the mean age at diagnosis was 18.6 years, with the youngest patient being 10, having a family history of MEN 1. These findings are consistent with the literature. We included 3 malignant insulinomas (25%). All presented with secondary hepatic metastases and were treated with chemoembolization, chemotherapy, or hepatic resection. One patient also had adrenal and kidney metastases receiving chemotherapy and PRRT. All patients with malignant insulinomas received treatment with somatostatin analogs.

Conclusion: Our findings are consistent with the literature, indicating that insulinomas are mostly benign, with a strong link to MEN 1 syndrome in younger patients. Malignant insulinomas, though rare, are frequently metastatic and require a comprehensive treatment strategy.

Key words: insulinoma, neuroendocrine tumors, insulin, multiple neuroendocrine neoplasia.