Usefulness of Thin-Slice Contrast-Enhanced Computed Tomography in Detecting Perforation Site in Congenital Biliary Dilatation: A Case Report.

The site of perforation is difficult to identify preoperatively in many cases with spontaneous perforation of congenital biliary dilatation (CBD). We report a case of spontaneous perforation of CBD in which the perforation site was identified preoperatively using thin-slice contrast-enhanced computed tomography (CT). The patient was a girl aged 1 year and 4 months. She was admitted to our hospital because of vomiting and diarrhea that had continued for 3 days prior to admission. Abdominal contrast CT on admission showed dilated common bile duct, thickening of the gall bladder wall, and marked ascites. In addition, an area of low density with a diameter of 1 cm was detected near the neck of the gallbladder. We evaluated the area via thin-slice contrast-enhanced CT and detected a defect in the wall of the bile duct. Cholangiography revealed abnormal confluence of the pancreaticobiliary duct and a protein plug in the common duct. A diagnosis of CBD with perforation of the bile duct was made, and surgery was performed. The intraoperative findings matched that seen on the enhanced CT. There are some reports of pseudocysts and fluid retention around the perforation site; however, no reports are found in which the perforation site was confirmed by preoperative CT. If localized fluid retention is observed in cases with biliary perforation, confirmation with thin-slice contrast-enhanced CT might be useful for identifying the perforation site.