title: Differential diagnosis of infantile choledochal cyst with or without biliary atresia.
abstract: BACKGROUND
  The choledochal cyst, a cystic dilatation of the biliary tree, in infancy may be associated with biliary atresia (BACH) or without biliary atresia (CH). Infants in both groups usually have similar clinical symptoms at presentation but different management and prognosis.
  
  
  METHODS
  We retrospectively identified 29 infants, aged younger than 1 year, who had surgically proven choledochal cysts from 1991 to 2004. They were diagnosed as CH in 18 patients and BACH in eleven. They had undergone preoperative abdominal ultrasonography (29 patients) and intravenous radionuclide cholangiography (IVRC) (19 patients).
  
  
  RESULTS
  The comparison of the clinical characteristics and laboratory examinations between the two groups showed that BACH patients had no sex predominance contrasting to female predominance in CH patients, more often presented with prolonged jaundice and clay-colored stool, and had higher bilirubin levels. In diagnosing BACH by ultrasonography, using the diameter of the extrahepatic cystic dilatation < or =1.5 cm but not atretic gallbladder further increased the sensitivity, specificity, positive and negative predictive rates (81.8%, 100%, 100%, 90% vs 54.5%, 88.8%, 75%, 76.2%, respectively), yielding an increased diagnostic accuracy (93.1% and 75.9%, respectively). In diagnosing BACH by IVRC, the sensitivity, specificity, positive and negative predictive value and diagnostic acCuracy were 100%, 70%, 75%, 100% and 84.2%, respectively.
  
  
  CONCLUSIONS
  We concluded that there were clinical and laboratory discrepancies between the two groups, including female predominance, prolonged jaundice, clay-colored stool, bilirubin levels and size of cyst. In diagnosing BACH, the accuracy of abdominal ultrasonography will be increased if we use the diameter of the extrahepatic cystic dilatation < or = l.5 cm but not atretic gallbladder as one of the diagnostic cretia. Hepatobiliary scintigraphy had less diagnostic accuracy than ultrasonography but can be added to exclude the diagnosis of BACH.
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan. huang817@adm.cgmh.org.tw
authors.forename: Fu-Chen
authors.initials: FC
authors.lastname: Huang
authors.forename: Kao-Pin
authors.initials: KP
authors.lastname: Hwang
mesh_terms: D001653:Bile Ducts, Intrahepatic / Q000473:pathology; D001656:Biliary Atresia / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002758:Cholangiography; D015529:Choledochal Cyst / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D004108:Dilatation, Pathologic; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D014463:Ultrasonography