Serendipitous Discovery and Characterization of Two Different Pathologies on 68Ga-DOTATATE and 68Ga-Exendin PET/CT in a Patient With Hyperinsulinemic Hypoglycemia Leading to Diagnosis of MEN-1

The complementary role of multi-tracer PET in deciphering 2 different pathologies in multiple endocrine neoplasia 1 (MEN-1) is illustrated in this report. A 22-year-old man, with a history of altered behavior over the past 1 year and suspected to have hyperinsulinemic hypoglycemia based on a positive 72-hour fasting test and CT abdomen revealing a lesion in the pancreas, was referred for 68 Ga-Exendin-4 PET/CT. The 68 Ga-Exendin PET/CT revealed focal uptake in the pancreatic lesion, and 68 Ga-DOTATATE PET/CT did not show any avidity in the pancreatic lesion; however, it demonstrated somatostatin receptor (SSTR) expression in a soft tissue mass, just posterior to the thyroid. Parathyroid adenoma and hyperparathyroidism were finally proven, and genetic testing was done, which came positive for the diagnosis of MEN-1 syndrome.