Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) in insulinomas: Indications and clinical relevance in a single investigator cohort of 47 patients.

Purpose: This study was aimed to investigate the role and relevance of endoscopic ultrasound-guided fine-needle aspiration biopsy in the diagnostic work-up of insulinomas.
Methods: We have analysed the frequency, clinical indications, success rate (obtaining diagnostic tissue), diagnostic accuracy (in comparison to the pathological diagnosis after surgery), complications, and tolerability of endoscopic ultrasound-guided fine-needle aspiration biopsy and the localization and size of the lesions in 47 consecutive patients (29 females, 18 males; 46 ± 15 years) who had surgery for insulinoma following fasting test and were explored by single investigator EUS 1994-2015.
Results: Endoscopic ultrasound-guided fine-needle aspiration biopsy was performed in 21 % (10/47) of the patients. The clinical indications for endoscopic ultrasound-guided fine-needle aspiration biopsy were non-conclusive result of fasting test (n = 7), missing toxicology (n = 2), suspected malignancy at EUS (n = 1), suspicious extra-pancreatic localization of the lesion (n = 1). The diagnostic success rate of the procedure was 80 % (8/10 cases), the diagnostic accuracy of the fine-needle aspiration biopsy 70 % (7/10 cases). The lesions undergoing endoscopic ultrasound-guided fine-needle aspiration biopsy were localized in the cauda (n = 5), corpus (n = 2), caput/processus uncinatus (n = 3), the diameter of the tumors was 21 ± 18 (10-70) mm. Only one accidental vascular puncture without any clinical complication occurred and all patients tolerated the procedure well.
Conclusions: In the majority of cases, positive fasting test, negative toxicology, and detection of a typical pancreatic lesion at endoscopic ultrasound is sufficient for the diagnosis of insulinoma and the definition of the appropriate surgical strategy. Based on our data, we suggest including endoscopic ultrasound-guided fine-needle aspiration biopsy in the diagnostic work-up of organic hyperinsulinism in selected patients with inconclusive or uncertain diagnosis before surgery.