Clinicopathological Features of Insulinoma: A Single Tertiary Center Experience

Abstract

Insulinoma is a rare pancreatic neuroendocrine tumor with an incidence of 1-4 cases per million. Here we present our 10 years of experience in 13 cases of insulinoma. We retrospectively reviewed all insulinoma patients diagnosed and treated between 2012 and 2022. Clinical and pathological features, diagnostic methods, and follow-up results of insulinoma patients were discussed. A total of 13 patients were included in this study (7 men, and 6 women). The mean age at the time of diagnosis was 58 (36.5-70.5) years. There is only one patient diagnosed with MEN-1 syndrome. The mean time from the onset of symptoms to the diagnosis was 15 (7-27.5) months. In the prolonged fasting test, symptomatic hypoglycemia occurred in all patients within 48 h. The median size of lesions was 15 (12-24) mm, and 46.2% of these lesions were isolated in the pancreatic tail. Ga-68 DOTATATE PET/CT detected lesions with 100% accuracy. Three patients met the criteria for malignant insulinoma. Octreotide LAR was given to 1 patient with metastatic disease and 1 patient who did not accept surgery. The metastatic patient received 8 cycles of Lu treatment and died after 51 months of follow-up. The diagnosis of insulinoma can be challenging. The 48-h fasting test period provided sufficient information for the diagnosis of insulinoma. Ga-68 DOTATATE PET/CT may be an alternative in cases where cross-sectional imaging cannot localize the pancreatic lesion.

Keywords: Hypoglycemia; Insulinoma; PanNET; Pancreas.

Fig. 1

MRI scan showing a single 12 mm tumor in the tail of the pancreas

Fig. 2

Ga-68 DOTATATE PET/CT showed increased radionuclide uptake in metastatic liver lesions and pancreatic neuroendocrine tumors