Classification of choledochocele.

Background/aims: Choledochocele is a rare abnormality of cystic or diverticular dilatation of the terminal intramural portion of the common bile duct. Because its anatomic form does not fit the criteria for pancreaticobiliary maljunction, reflux of bile or pancreatic juice has not been discussed in relation to choledochocele. Considering the flow of bile and pancreatic juice, the authors developed a new classification of choledochocele, and investigated associated pancreaticobiliary diseases.

Methodology: We reviewed 82 cases of choledochocele, and classified them into three groups on cholangiopancreatographic findings; Type A (n=27): cystic dilatation of the common channel, Type B (n=31): cystic dilatation of the intramural bile duct forming the common channel, Type C (n=24): cystic dilatation of the intramural bile duct opening into the duodenum separately from the pancreatic duct.

Results: Biliary carcinoma was associated with 2 cases of Type A and 1 case of Type B choledochocele. Acute pancreatitis occurred in 10 Type A and 6 Type B choledochoceles. Biliary pancreatic reflux was reported in 4 cases of Type A and 1 case of Type B. Marked elevation of amylase in the bile was reported in 5 Type A and 5 Type B choledochoceles.

Conclusions: In choledochoceles forming a common channel (Type A and B), two-way regurgitation may occur, and induce acute pancreatitis and biliary carcinoma. This classification of choledochocele is useful for analysis of pathophysiology and determination of therapeutic strategy.