ENDOSCOPY ULTRASOUND GUIDED RADIOFREQUENCY ABLATION OF FUNCTIONING INSULINOMA IN A SYMPTOMATIC PATIENT UNFIT FOR SURGERY

Insulinoma is the most common functioning neuroendocrine tumor of the pancreas. The gold-standard therapeutic approach for insulinoma is surgery for removal, histology and immunochemistry. Radiofrequency ablation (RFA) is applied in treatment of several malignancies achieving tumor necrosis by cell protein denaturation. Energy is provided by an RFA current generator, connected to an electrode needle placed into tumor under image guidance. The lesions created have variable diameters, depending on the intensity of the current used, the active tip length, and the treatment duration. Recently a novel RFA needle (EUSRA RF Electrode; STARmed, Koyang, Korea) has been developed for use under endoscopic ultrasound (EUS) guidance, using a 19 G water-cooled needle, with an active tip connected to a radiofrequency generator.

We describe the successful use of endoscopy ultrasound (Eus) guided radiofrequency ablation (RFA) of an insulinoma in an 76-year-old female patient. The patient was referred to our hospital for multiple episodes of severe nightly hypoglycemia with a minimal glucose concentration 32 mg/dl. A focal lesion compatible with an insulinoma measuring 10 mm in diameter was localized by endoscopic ultrasound and CT scan in the tail of the pancreas. EUS-guided fine needle biopsy (FNB, 19 G) revealed a pancreatic neuroendocrine tumor (pNET) with a Ki67 proliferative index of < 1%, consistent with a G1 grading and with immunohistochemistry test compatible with insulinoma. For high surgical risk due to patient's comorbidities, the resection of the tumor was not considered. The medical treatment failed to control the symptoms of hypoglycemia sufficiently. Using eus-guided RFA the insulinoma was successfully ablated. No post interventional complications occurred. During a 6 week follow-up, episodes of hypoglycemia were absent.

In conclusion Eus guided RFA is feasible, safe and effective for the treatment of pancreatic insulinomas. The procedure should be reserved for the treatment of symptomatic patients who are no candidates for surgical therapy.