ENDOSCOPIC ULTRASOUND-GUIDED RADIOFREQUENCY ABLATION USED IN THE TREATMENT OF INSULINOMA

Abstract

INTRODUCTION/BACKGROUND
Surgical excision used to be the mainstay of curative treatment for insulinoma. In recent years, endoscopic ultrasound-guided radiofrequency ablation (EUS-guided RFA) has been used as a curative technique for insulinoma. Here, we report 2 cases of insulinoma with solitary lesions which showed clinical improvement following treatment with EUS-guided RFA.

CASE
The first case involved a 43-year-old Malay male, nondiabetic, who came with reduced consciousness during the fasting month of Ramadan. A low random blood sugar of 1.4 mmol/L was accompanied by elevated insulin (8.3 mIU/L) and C-peptide (427 pmol/L). Contrast-enhanced CT showed a pancreatic lesion in the body measuring 1.4 x 1.6 cm. EUS confirmed the presence of a 1.5 cm hypoechoic lesion at the same location. He underwent 3 cycles of EUSguided RFA without any complications. After the second cycle of RFA, diazoxide was discontinued and there was no recurrence of hypoglycaemia. The second case involved a 59-year-old male who presented with recurrent episodes of giddiness and sweating for the past 1 year. Each episode resolved with food intake. A 72-hour prolonged fast revealed hyperinsulinaemic hypoglycaemia (RBS 2.3 mmol/L, elevated insulin 1064 pmol/L and elevated C-peptide 94.7 pmol/L). Insulin autoantibody was negative. Initial imaging with contrastenhanced CT and ⁶⁸Gallium-DOTATATE scan failed to localize any pancreatic lesion. However, subsequent EUS detected a lesion at the pancreatic neck measuring 1.0 x 1.2 cm. Fine needle aspiration reported a pancreatic neuroendocrine tumour with positive staining for chromogranin and synaptophysin. He underwent 3 cycles of EUS-guided RFA without complications. His hypoglycaemia symptoms resolved after the 3rd cycle of RFA.

CONCLUSION
EUS-guided RFA can be a potential consideration in treating insulinoma with solitary lesions <2 cm with no evidence of metastasis. It is minimally invasive with low periprocedural complication risk. Longer followup is needed in both patients to assess long-term clinical effectiveness and recurrence.