Insulinoma Diagnosis and Management

Diagnostic Criteria

The American College of Endocrinology recommends a supervised 48-72 hour fast as the gold standard diagnostic test for insulinoma, performed until hypoglycemia occurs or the time limit is reached, with criteria including blood glucose <40-45 mg/dL, insulin level >3 mcIU/mL, C-peptide ≥0.6 ng/mL, proinsulin levels ≥5 pmol/L, and insulin-to-glucose ratio ≥0.3 1
The Endocrine Society suggests that elevated C-peptide is critical for differentiating endogenous hyperinsulinemia (insulinoma) from exogenous insulin administration 1

The European Society of Endocrinology recommends beginning with dual-phase multidetector CT or MRI (sensitivity 57-94% and 74-94% respectively) to rule out metastatic disease and provide initial localization 1
The American Gastroenterological Association suggests that endoscopic ultrasound (EUS) should be performed in all cases, as it achieves 82-93% sensitivity and allows tissue sampling via fine needle aspiration 1
The Society of Nuclear Medicine recommends considering 68Ga-DOTATOC/DOTATATE PET/CT, which demonstrates the highest sensitivity (87-96%), when conventional imaging is negative 1

The American College of Surgeons recommends surgical resection as the optimal treatment for locoregional insulinomas, with a cure rate of 90% 1
The European Society for Medical Oncology suggests that diazoxide is the first-line medical therapy for managing hypoglycemia due to hyperinsulinism, with everolimus as an alternative for preoperative stabilization 1, 2
The American Diabetes Association recommends stabilizing glucose levels with dietary management (frequent small meals) as the first-line approach before any intervention 1