Utility of liquid-based cytology in the evaluation of endoscopic ultrasound-guided fine-needle aspiration: Comparison with the conventional smears

Background and aim: Recently, endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) has been introduced in the diagnosis of pancreatic lesions, adjacent lymph nodes, and organs. To investigate the usefulness of liquid-based cytology (LBC) in EUS-FNA, we compare the efficacy of the conventional smear (CS) and LBC in EUS-FNA specimens. Methods: Forty-three paired LBC and CS slides were obtained using a split sample protocol. The specimen adequacy and diagnostic values were compared. Results: The adequate cases for diagnosis were 36 (83.7%) in CS and 22 (51.2%) in LBC. Inadequate samples were mostly obtained from lymph nodes: 6 cases in CS and 17 in LBC. The sensitivity, specificity, and accuracy of CS and LBC were as follows: 90.5%, 95.5%, and 93.0% in CS, respectively, and 57.1%, 100%, and 79.1% in LBC. The false-negative and false-positive rates were 4.7% and 2.3% in CS, respectively, and 20.9% and 0% in LBC. The overall agreement of CS and LBC for the diagnosis of malignancy was high (κ= 0.616). Conclusions: CS is a more effective and adequate preparation method for use in EUS-FNA-based diagnosis. Considering the split sample protocol of this study, LBC is a comparable diagnostic tool to CS in the evaluation of EUS-FNA specimens.