Unexplained common bile duct dilatation with normal serum liver enzymes: diagnostic yield of endoscopic ultrasound and follow-up of this condition.

BACKGROUND: There is scant literature about common bile duct (CBD) dilatation with normal liver function tests (LFTs). AIMS: The aims of this study were to assess the diagnostic yield of endoscopic ultrasound (EUS) in patients with CBD dilatation, normal LFTs, and prior inconclusive imaging tests, and to assess the natural history of these subjects. METHODS: We retrospectively reviewed our EUS database for patients referred for evaluation of CBD dilatation, normal LFTs, and prior inconclusive imaging. We excluded patients with a prior endoscopic retrograde cholangiopancreatography or a history of biliary obstruction, pancreatitis, or jaundice. Follow-up data were retrieved from medical records or by calling the general practitioners, referring specialists, patients, or their closest relatives. RESULTS: A total of 57 patients were enrolled. The mean CBD diameter was 12.5±3.6 mm. The majority of patients (50.8%) were asymptomatic. Abnormal EUS findings were recorded in 12 (21%) subjects: 6 patients had a periampullary diverticulum, 2 had ampullary adenoma, 2 had signs of chronic pancreatitis, 1 had a cancer of the pancreatic head, and 1 had a 7 mm CBD stone. Neither age, sex, prior cholecystectomy, clinical presentation, CBD diameter, nor a dilated main pancreatic duct were predictors of abnormal EUS findings. None of the patients complained of biliary symptoms or showed abnormal LFTs on long-term follow-up. CONCLUSIONS: CBD dilatation with normal liver chemistry is not always a benign condition. Even when prior imaging tests are negative, EUS may allow to diagnose conditions overlooked by standard diagnostic imaging.