Endocrine Abstracts

Background: Insulinoma is a rare pancreatic neuroendocrine tumor, occuring in 1-4 people per million in the general population. It may appear at any age, slightly more common in female than male. Most are benign and solitary. Endogenous hyperinsulinism determines symptomatic hypoglycemia. However, the nonspecific symptoms and small size of these tumors lead to challenges in diagnosis and localization. The treatment of choice is surgical resection, but mini-invasive ablative therapies can be used in selected pacients.

Aim: We present the case of a benign insulinoma treated with endoscopic ultrasound guided radiofrequency ablation.

Case report: A 52-year-old woman presented with a 6 months history of repeated episodes of weakness, fatigue and irritability in a fasting state. Symptoms improved with meals. Over that period of time she gained 10 kilograms. She denied having diabetes or any visual field issues, headaches, behavior change, loss of consciousness or seizures. It is decided that the pacient should undergo a prolonged supervised fasting test and within 30 hours the pacient had symptomatic low plasma glucose level of 38 mg/dl (normal range 74-106) and inappropriately high plasma insulin level of 10.1 μU/ml (normal range 6-35). Following confirmation of an insulinoma, an abdominal computed tomography scan was done for the preoperative localization, but the result was inconclusive. Endoscopic ultrasonography with fine needle aspiration was performed, confirming a well-differentiated pancreatic neuroendocrine tumor G1, with a diameter of 12/10 mm, located at the junction between the pancreatic isthmus and the body. Endoscopic ultrasound guided radiofrequency ablation (EUS-RFA) using a 19G needle represented the treatment option, as an alternative to surgery and insulinoma was successfully removed. The postoperative evolution was favorable, with minimal abdominal pain treated with analgesic drugs. One week following EUS-RFA, the pacient was asymptomatic, the laboratory tests normalised and during the 3 months follow-up visit, the plasma glucose remained within normal range and the pacient had no active complaints.

Conclusion: This case highlights that an accurate preoperative localization of an insulinoma dictates the management and that EUS-RFA may be a potential alternative to surgery in selected cases. However, more studies are needed to establish the long-term efficacy.