SUN-278 Long-term Insulinoma: A Case Of 30 Years Of Unrecognized Hypoglycemia

Abstract Disclosure: J.M. Matos-Chaparro: None. A. Franjul: None. N. Roman Velez: None. N. Canevaro: None. M. Rosado: None. Insulinoma is a rare, benign neuroendocrine tumor originating from the pancreatic beta cells, characterized by excessive insulin secretion leading to recurrent episodes of hypoglycemia. The clinical presentation can be nonspecific, with symptoms ranging from sweating, tremors, and confusion to more severe manifestations such as seizures or loss of consciousness, which can complicate early diagnosis and delay treatment. We present a case of a 76-year-old female with a 30-year history of recurrent hypoglycemic episodes. Diagnosis was confirmed through clinical evaluation, biochemical testing showing elevated insulin and C-peptide levels during hypoglycemia, and imaging studies revealing a pancreatic lesion.The patient’s management was complex, as she was a poor surgical candidate due to her severe obesity, bedridden status, and concurrent multifocal candidiasis. A 72-hour fast test revealed a capillary glucose of 40 mg/dL, which increased by 25 mg/dL within 15 minutes after glucagon administration, suggesting preserved hepatic glucose reserves. Biochemical tests confirmed elevated insulin (30 µU/mL) and C-peptide (8.31 ng/mL) levels, supporting the diagnosis. Magnetic resonance imaging (MRI) identified a 1.7 cm enhancing lesion at the tail of the pancreas. Given the patient’s poor surgical candidacy, she was initially treated with octreotide, a somatostatin analog that inhibits insulin and glucagon release. However, the patient experienced multiple side effects, including tachycardia, prompting discontinuation of octreotide and initiation of diazoxide. Diazoxide, which inhibits insulin secretion by opening K-ATP channels and preventing calcium influx into beta cells, led to a marked reduction in hypoglycemic episodes.This case underscores the diagnostic challenges of insulinoma, particularly in patients with a prolonged clinical course where symptoms overlap with other conditions, such as idiopathic hypoglycemia, or in those with atypical presentations. It highlights the importance of maintaining a high index of suspicion for insulinoma in patients with recurrent or unexplained hypoglycemia, even in cases with a prolonged history. Moreover, the case emphasizes the role of a multidisciplinary approach, integrating clinical evaluation, biochemical testing, and advanced imaging techniques, to ensure accurate diagnosis and optimal management. The choice of treatment must be individualized based on patient comorbidities, with surgical resection remaining the gold standard in most cases, while pharmacological management such as diazoxide offers an alternative for non-surgical candidates. Effective management is crucial to mitigate the potentially serious consequences of prolonged hypoglycemia, including neurological impairment and even death. Presentation: Sunday, July 13, 2025