LAUSR

The diagnostic efficacy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of pancreatic solid masses varies widely depending on the presence of rapid onsite evaluation (ROSE) and the type of cytology preparations. The present study aims to compare the diagnostic efficacy of cytology smears (CS) and cell block (CB) with ROSE versus Thinprep slides (TpS) with CB without ROSE in diagnosing pancreatic solid masses. Performed retroprospective review of 56 patients (2017-2018) with surgically confirmed pancreatic neoplasms including cytology preparation type and comparison of diagnostic efficacies. Out of 56 patients who underwent surgical resection, 30 patients were diagnosed with pancreatic ductal adenocarcinoma (PDAC) and 26 with pancreatic neuroendocrine tumor (PNET) or solid pseudopalliary neoplasm (SPN). Out of 30 surgically removed PDACs, 20 patients had prior cytology specimens while 10 had surgical core biopsies. Of the 20 cytology specimens, 12 patients had ROSE with concurrent CS and CB, and all cases were diagnosed as positive. Out of the 8 patients without ROSE, 3 patients (1 with bile duct brush, 2 with TpS and CB) were diagnosed as positive. The diagnostic efficacy was 100% (12/12) in patients with ROSE and CS compared to 37.5% (3/8) in patients without ROSE. In 26 non-PDAC cases, 21 patients had cytology specimens and 5 had surgical biopsies. Seventeen cases with ROSE and immunohistochemical stains (IHC) on CB were diagnosed as positive, while 4 cases without ROSE and IHC received atypical diagnoses, resulting in a decreased diagnostic efficacy from 100% (17/17) to 0% (0/4). ROSE with CS and CB are superior to TpS and CB in diagnosing solid pancreatic masses. ROSE with IHC on CB is crucial for diagnosing PNET and SPN, while CS and CB are important for PDAC diagnosis.