The role of endoscopic ultrasound in evaluating patients with bile duct dilation of unclear etiology.

OBJECTIVE Bile duct dilation (BDD) of unclear etiology is a common indication for further imaging via endoscopic ultrasound (EUS). We aimed to assess the yield of EUS in determining BDD etiology in patients with prior non-diagnostic imaging studies. METHODS A retrospective chart review was performed at a single, tertiary-care university hospital for patients referred for EUS for BDD with or without pancreatic duct dilation (PDD). EUS-guided fine needle aspiration (FNA) was performed if a focal lesion was identified. Cases with an etiology of BDD diagnosed or strongly suggested by prior imaging were excluded. EUS findings believed to represent a structural cause for BDD included a wide range of pancreaticobiliary and luminal pathology as well as patients' clinical factors. RESULTS In total, 307 patients were identified. Findings to explain BDD were found by EUS in 213 patients for a diagnostic yield of 69.4%. Patients with jaundice were significantly more likely to receive a diagnosis by EUS than those without (78.8% vs 55.3%, P < 0.01). Notably, 8.1% of patients with normal liver function test (LFT) had a EUS-diagnosed malignancy. Patients' age, narcotic use, concurrent PDD and prior cholecystectomy did not appear to influence the EUS yield. CONCLUSIONS EUS continues to play a substantial role in evaluating BDD of unclear etiology, most notably in patients with jaundice. In addition, given that 8.1% of asymptomatic patients without jaundice or abnormal LFT had malignancy diagnosed on EUS, the use of EUS for BDD of unclear etiology remains warranted. TAKE HOME MESSAGES The diagnostic yield of EUS in patients referred for bile duct dilation of unclear etiology was substantial at 69.4%. Nearly 1/5 (19.5%) of patients referred for evaluation of a dilated bile duct failed to have confirmation of bile duct dilation on EUS. Even among patients with normal LFT, a malignancy was found by EUS in 8.1% of patients. Because important pathology, including malignancy, was frequently discovered by EUS in patients with seemingly incidental bile duct dilation, the routine use of EUS and EUS-FNA/FNB for this indication seems warranted.