Choledochal cyst associated the with anomalous union of pancreaticobiliary duct (AUPBD) has a more grave clinical course than choledochal cyst alone

OBJECTIVE Since choledochal cyst is frequently associated with the anomalous union of pancreaticobiliary duct (AUPBD), AUPBD has been regarded to be the etiologic factor of choledochal cyst. However, the clinical significance of AUPBD an patients with choledochal cyst has not been clearly defined. Therefore, to clarify the significance of AUPBD in choledochal cyst patients, we compared the clinical features of patients with choledochal cyst according to the presence or absence of AUPBD. METHODS Among 52 cases which were diagnosed as choledochal cyst out of 5,037 ERCP referrals between August 1990 and December 1996, we selected 44 cases, in which the pancreaticobiliary junction was clearly visualized on cholangio-pancreaticography. These cases were divided into AUPBD-present group (n = 28) and AUPBD-absent group (n = 16). Clinical features were compared between the two groups. Furthermore, in AUPBD-present group, clinical data were also analyzed according to Kimura's classification of AUPBD. RESULTS In our study, AUPBD was associated with choledochal cyst in 28 (64%) cases. AUPBD was found only in type I and IV according to Todani's classification of choledochal cyst. There were no significant differences between the AUPBD-present group and the AUPBD-absent group in the incidence of gallstone disease, while the incidence of acute inflammation was 93% (26/28) in the AUPBD-absent group (p < 0.01). Carcinoma developed only in the AUOBD-present group (9/28, 32%) (p < 0.05). Pancreatic disorders (i.e. pancreatic stone, pancreatitis or pancreatic cancer) occurred in 12 of 28 cases in the AUPBD-present group (43%), while only in 1 of 16 cases in the AUPBD-absent group (6%) (p < 0.05). CONCLUSION AUPBD associated with choledochal cyst may have implications not only as a possible etiologic factor but also as an important factor that may affect the clinical course, surgical planning and prognosis. In cases with choledochal cyst, we should make an effort to evaluate the presence of AUPBD.