[Recurrent hypoglycemia due to an occult insulinoma]

Area of Science:

• Endocrinology
• Diagnostic Imaging
• Oncology

Background:

• Recurrent hypoglycemia can significantly impact patient quality of life.
• Accurate diagnosis of the underlying cause is crucial for effective management.
• Insulinoma, a rare pancreatic tumor, is a common cause of endogenous hyperinsulinemic hypoglycemia.

Observation:

• A 64-year-old woman experienced recurrent hypoglycemia.
• Standard imaging (ultrasound, CT, MRI) failed to identify the tumor.
• Prolonged fasting test indicated an elevated "amended" insulin-glucose ratio.

Findings:

• Contrast-enhanced endoscopic ultrasound and (68)gallium-DOTA-exendin-4 PET/CT successfully localized the suspected insulinoma.
• Histological confirmation post-surgery verified the insulinoma diagnosis.
• Postoperative hypoglycemia resolved, indicating successful tumor removal.

Implications:

• The prolonged fasting test remains the gold standard for insulinoma diagnosis.
• Novel imaging modalities, including endoscopic ultrasound and PET/CT, are valuable adjuncts.
• Early and accurate diagnosis through advanced imaging improves patient outcomes for insulinoma.