Magnetic resonance cholangiopancreatography diagnosis of choledochal cyst involving the cystic duct: report of three cases.

Here we describe three cases of choledochal cyst involving the cystic duct or isolated dilatation of the cystic duct. All cases were visualised on MR cholangiopancreatography (MRCP) imaging. We report findings of ultrasonography, CT and MRCP. These cases are extremely rare; nine cases have been reported in the English-language literature. This anomaly was not included in Todani's classifications of choledochal cysts, a system that is accepted worldwide. We think that this variant anomaly will be included in this classification system in the near future.