Association between insulinoma and adrenal insufficiency in a patient with type 2 diabetes: a case report

Samir Mkaouer; Khessairi Nadia; Merhbene Yasmine; Kamoun Elyes; Yazidi Meriem; Oueslati Ibtissem; Chaker Fatma; Chihaoui Melika

doi:10.1530/endoabs.99.EP256

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Endocrine Abstracts (2024) 99 EP256 | DOI: 10.1530/endoabs.99.EP256

ECE2024 Eposter Presentations Endocrine-Related Cancer (90 abstracts)

Association between insulinoma and adrenal insufficiency in a patient with type 2 diabetes: a case report

Samir Mkaouer ¹ , Khessairi Nadia ¹ , Merhbene Yasmine ¹ , Kamoun Elyes ¹ , Yazidi Meriem ¹ , Oueslati Ibtissem ¹ , Chaker Fatma ¹ & Chihaoui Melika ¹

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¹La Rabta University Hospital, Endocrinology Department, Tunis, Tunisia

Introduction: Insulinomas are rare pancreatic endocrine tumors causing severe hypoglycemia in non-diabetic patients. We report a case of a rare association between insulinoma and type 2 diabetes.

Presentation of the case: A 65-year-old diabetic patient presented with a one year history of recurrent hypoglycemia even after the withdrawal of antidiabetic drugs. First, a functional hypoglycemia was suspected and an oral glucose tolerance test showed hypoglycemia after 4 hours confirming the diagnosis. We recommended split diet with acarbose. Due to the appearance of signs of neuroglycopenia, the patient was started on a 72-hour fast, and within 10 hours, he had a hypoglycemic episode. The subsequent laboratories drawn revealed venous hypoglycaemia (23 mg/dl), elevated insulin (15.75 UI/l), elevated C peptide (4.81 ng/ml) and negative sulfonylureas screening. The diagnosis of insulinoma was confirmed and an abdomen CT scan revealed a 17 mm pancreatic nodule. In addition to that, the cortisol level drawn during his hypoglycemia revealed that the patient had an inadequate adrenal response to stress. The serum cortisol peak was 14.7 µg/dl and ACTH level was 14.09 ng/l confirming the secondary adrenal insufficiency (SAI). He underwent a left pancreatectomy. One month after surgery, serum glucose levels had increased and the SAI had disappeared with basal cortisol level at 34 µg/dl.

Conclusion: The coexistence of insulinoma and type 2 diabetes is rare and the diagnostic process is often challenging. The association of SAI and insulinoma has been described yet the pathophysiological mechanism remains poorly elucidated. Therefore, precaution is needed in diagnosis even if there is an obvious cause of hypoglycemia.