Diagnostic Performance of Endoscopic Ultrasound (EUS)/Endoscopic Ultrasound - Fine Needle Aspiration (EUS-FNA) Cytology in Solid and Cystic Pancreatic Neuroendocrine Tumours

Background & Aims: Our study aimed to assess the sensitivity of EUS and EUS-FNA for pancreatic neuroendocrine tumors (pNETs) and compare performance over two consecutive 4 year 2 month periods, to investigate the comparative performance between solid and cystic pNETs and determine the incremental yield of EUS +/- FNA in individuals with a mass not diagnosed as a pNET after cross-sectional imaging. Methods: A retrospective review of a prospectively maintained database was carried out to identify all pNET patients who underwent EUS-FNA between April 2003 and September 2011. Results: A final diagnosis of solid and cystic pNETs was made in 43 and 10 patients, respectively. Overall, the yield of combined EUS imaging and cytology was significantly higher than that of CT and/or MRI (p < 0.05) across all groups [solid (83.7% vs. 41.8%), cystic (70% vs. 10%) and combined solid-cystic (81.1% vs. 35.8%)]. The yield of combined EUS imaging and cytology was significantly better than EUS imaging alone (p<0.05) in the solid (83.7% vs. 58%) and combined pNET cohort (81.1% vs. 52.8%) of patients. After a non-diagnostic CT and or MRI, EUS/EUS-FNA confirmed pNET in 19 out of 25 patients (76.0%) with solid pNETs and 6 out of 9 patients (66.7%) with cystic pNETs. Conclusion: EUS and EUS-FNA had a significant clinical impact in the 25/34 of cases where pNET was not suspected after initial cross-sectional imaging.