Background and study aims: Although abdominal ultrasonography (US) is a good initial screening method for detection of biliary tract disease, we sometimes encounter patients who only have findings of dilatation of the common bile duct (CBD) on US, without specific biliary symptoms or jaundice. This study aimed to evaluate the causes and clinical significance of dilatation of the CBD in patients without biliary symptoms, jaundice, or causative lesions at US.
Patients and methods: A total of 77 patients who had no biliary symptoms and whose internal CBD diameter was more than 7 mm, without definite causative lesions on US, were enrolled. Of these, 49 underwent endoscopic retrograde cholangiopancreatography (ERCP) and 28 underwent follow-up US or computed tomography (CT) instead of ERCP. We excluded patients whose bilirubin level had increased beyond the upper normal level or who had previous history of upper abdominal surgery including cholecystectomy.
Results: The ERCP findings were as follows: no lesion in 20 patients (40.8%), juxtapapillary duodenal diverticulum (JDD) in 11 (22.5%), benign stricture in ten (20.4%), distal CBD mass in two (4.1%), choledochal cyst in two (4.1%), anomalous union of the pancreaticobiliary duct (AUPBD) in two (4.1%), and choledochal cyst with AUPBD in two (4.1%). There were no differences in age or in alkaline phosphatase or gamma-glutamyl transpeptidase (GGT) levels between the patients who had causative lesions revealed at ERCP and those who did not. Among the 28 patients who did not undergo ERCP, 12 had returned to normal and eight had no change in CBD diameter on follow-up US. Among eight patients who underwent CT, there were four with normal findings, one with JDD, and three with suspected choledochal cysts.
Conclusions: We detected a significant number of causative biliary tract lesions in asymptomatic adults with dilatation of the CBD on routine abdominal US; no laboratory or demographic parameters were useful for discrimination. Further diagnostic study will be helpful for the early diagnosis of biliary tract disease in such patients.