Needle-based confocal endomicroscopy in the discrimination of mucinous from non-mucinous pancreatic cystic lesions

BACKGROUND: Pancreatic cystic lesions (PCLs) are considered a precursor of pancreatic cancer. Needle-based confocal endomicroscopy (nCLE) is an imaging technique that enables visualization of the mucosal layer to a micron resolution. Its application has demonstrated promising results in the distinction of PCLs. This study evaluated the utility of nCLE in patients with indeterminate PCLs undergoing endoscopic ultrasound fine-needle aspiration (EUS-FNA) to distinguish mucinous from non-mucinous lesions. AIM: To evaluate the accuracy of nCLE in indeterminate PCLs undergoing EUS-FNA to distinguish mucinous from non-mucinous lesions. METHODS: Patients who required EUS-FNA between 2015 and 2017 were enrolled prospectively. During EUS-FNA, confocal imaging, analyses of the tumor markers carcinoembryonic antigen and amylase, and cytologic examination were conducted. All patients were followed for at least 12 mo and underwent laboratory testing and computed tomography scanning or magnetic resonance imaging. nCLE videos were independently reviewed by 6 observers to reach a final diagnosis (mucinous vs non-mucinous) based on criteria derived from previous studies; if there was disagreement > 20%, a final diagnosis was discussed after consensus re-evaluation. The sensitivity, specificity, and accuracy of nCLE were calculated. Adverse events were recorded. RESULTS: Fifty-nine patients were included in this study. Final diagnoses were derived from surgery in 10 patients, cytology in 13, and imaging and multidisciplinary team review in 36. Three patients were excluded from final diagnosis due to problems with nCLE acquisition. Fifty-six patients were included in the final analysis. The sensitivity, specificity, and accuracy of nCLE were 80% [95% confidence interval (CI): 65-90], 100% (95%CI: 72-100), and 84% (95%CI: 72-93), respectively. Post-procedure acute pancreatitis occurred in 5%. CONCLUSION: EUS-nCLE performs better than standard EUS-FNA for the diagnosis of indeterminate PCL.