Background/Aims: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a standard procedure for obtaining tissue from lesions near the gastrointestinal lumen. However, there is a scarcity of information on the diagnostic performance of EUS-FNA for abdominal lymphadenopathy of unknown causes. To assess the accuracy of EUS-FNA in diagnosing abdominal lymphadenopathy of unknown etiology. Methods: The EUS records of patients with undiagnosed abdominal lymphadenopathy between 2010 and 2015 were reviewed. Results: A total of 42 patients were included in this study. Adequate specimens were obtained from 40 patients (95%). The final diagnoses were metastatic cancer (n=16), lymphoma (n=9), tuberculosis (n=8), inflammatory changes (n=6), and amyloidosis (n=1). For diagnosing malignancy, EUS-FNA had a sensitivity of 84.6%, specificity of 95.7%, positive predictive value of 91.7%, negative predictive value of 91.7%, and area under the receiver operating characteristic curve (AUROC) of 0.901. For the diagnosis of lymphoma, EUS-FNA was 100% accurate when combined with cytologic evaluation and immunohistochemical staining. The diagnostic sensitivity decreased to 75%, whereas the specificity remained 100%, for tuberculosis. The overall AUROC was 0.850. No procedure-related complications occurred. Conclusions EUS-FNA showed high diagnostic performance for abdominal lymphadenopathy of unknown causes, especially malignancy, lymphoma, and tuberculosis. Therefore, it is a crucial diagnostic tool for this patient population.

Background/Aims: Endoscopic ultrasonography (EUS) is warranted when cross-sectional imaging demonstrates common bile duct (CBD) dilatation without identifiable causes. This study aimed to assess the diagnostic performance of EUS in CBD dilatation of unknown etiology. Methods: Retrospective review of patients with dilated CBD without definite causes undergoing EUS between 2012 and 2017. Results: A total of 131 patients were recruited. The mean age was 63.2±14.1 years. The most common manifestation was abnormal liver chemistry (85.5%). The mean CBD diameter was 12.2±4.1 mm. The area under the receiver operating characteristic curve (AUROC) of EUS-identified pathologies, including malignancy, choledocholithiasis, and benign biliary stricture (BBS), was 0.98 (95% confidence interval [CI], 0.95-1.00). The AUROC of EUS for detecting malignancy, choledocholithiasis, and BBS was 0.91 (95% CI, 0.85-0.97), 1.00 (95% CI, 1.00-1.00), and 0.93 (95% CI, 0.87-0.99), respectively. Male sex, alanine aminotransferase ≥3× the upper limit of normal (ULN), alkaline phosphatase ≥3× the ULN, and intrahepatic duct dilatation were predictors for pathological obstruction, with odds ratios of 5.46 (95%CI, 1.74-17.1), 5.02 (95% CI, 1.48-17.0), 4.63 (95% CI, 1.1-19.6), and 4.03 (95% CI, 1.37-11.8), respectively. Conclusions EUS provides excellent diagnostic value in identifying the etiology of CBD dilatation detected by cross-sectional imaging.