No communication between the bile duct and intraductal papillary neoplasm of the bile duct on imaging.

As a rare biliary tract tumor, intraductal papillary neoplasm of the bile duct (IPNB) is most common in elderly men and can progress to cholangiocarcinoma- (CCa) if left untreated. It is reported that IPNB usually communicates with the bile duct. As a result, the downstream bile ducts are imaged asymmetrically dilated. However, a case of IPNB that we report here is different. Enhanced MRI revealed a lack of connectivity with the bile duct in this case. Based on this, the purpose of this case study is to suggest that the majority of imaging doctors should widely understand the various imaging manifestations of the disease to avoid misdiagnosis. In addition, although this feature was not indicated by ultrasound in this case, given previous studies and considering the convenience and non-ionizing radiation damage of CEUS, we recommend its use as a screening method for IPNB to improve diagnostic accuracy.