Spontaneous perforation of choledochal cyst: a study of 13 cases.

Of the 187 cases of infantile choledochal cyst treated at our hospitals, we encountered 13 with spontaneous perforation. All cases were under 4 years old. Eight cases were found to have biliary peritonitis and 5 had a sealed perforation. The shape of the extrahepatic bile duct was cystic in 8 and fusiform in 5. The cyst wall around the perforation was filmy and bile was found to be oozing through the thinned wall. Nine perforations were single while 4 cases had multiple perforations. Four of 17 perforations occurred in the posterior part of the cyst wall. Only 1 case of perforation was associated with protein plugs in a common channel, while 7 of the 10 cases of choledochal cyst requiring percutaneous biliary drainage due to signs of raised intrabiliary pressure were found to have protein plugs. We consider that spontaneous perforation of a choledochal cyst is not rare in infancy. The etiology of a perforation must be epithelial irritation of the biliary tract due to refluxed pancreatic juice caused by pancreatico-biliary malunion associated with mural immaturity due to infancy, rather than an abnormal rise in ductal pressure or congenital mural weakness at a certain point.