MRI manifestations of adult choledochal cysts associated with biliary malignancy: a report of ten cases

Background

To retrospectively review the MRI imaging features of adult choledochal cysts associated with biliary malignancy.

Patients and methods

Ten out of 72 cases of adult choledochal cysts were found to be associated with biliary malignancy between January 1, 2003 and April 1, 2011 in our hospital database. The following MRI findings of these ten patients were retrospectively reviewed: the type of choledochal cysts, the presence of anomalous union of the pancreaticobiliary duct (AUPBD), manifestations of biliary malignancy, and concomitant findings.

Results

Among the ten patients, there were five type I and five type IVA choledochal cysts. AUPBD was noted in four cases. The biliary malignancy was diagnosed as cholangiocarcinoma in seven cases (70.0%) and as gallbladder cancer in three cases. Cholangiocarcinoma manifested with irregularly thickened cyst wall (n = 2), mass with irregularly thickened cyst wall (n = 4), or multiple papillary nodules without thickened cyst wall (n = 1). Most of them showed mark enhancement (n = 4) after contrast administration. Gallbladder cancer appeared as mass with irregular thickening of the gallbladder wall with inhomogeneous enhancement. Concomitant findings included liver invasion or metastases in five cases, lymph node metastases in two cases, cholangitis and/or hepatic abscess in two cases, biliary stones in three cases. The type of choledochal cysts and the extent of malignant tumor invasion revealed by MRI were consistent with the surgical findings.

Conclusion

Most malignancies associated with choledochal cysts are cholangiocarcinoma and gallbladder cancer. MRI is a reliable method for the detection of choledochal cysts with biliary malignant changes. MR features such as irregular thickening of the gallbladder wall or cyst wall, mass or papillary nodules are suggestive of biliary malignant changes.