Etiological classification and treatment strategies for secondary bile duct dilatation.

Secondary intra- and extrahepatic bile duct dilatation is a very common condition that can be caused by several diseases. However, it has been rarely discussed in the specialized literature. Moreover, no distinct etiology can be determined in some cases, which hampers the diagnosis and treatment. Here, we discuss the etiological classification and treatment strategies of secondary intra- and extrahepatic bile duct dilatation based on an extensive literature review, as well as our experimental research and clinical experience. The etiology of secondary intra- and extrahepatic bile duct dilatation can be classified in different ways. From a clinicopathological perspective, it can be classified into obstruction-, lesion-, and compression-induced dilatation. Treatment varies depending on the cause. For example, endoscopic dilation or stenting is used for biliary strictures, laparoscopic choledochectomy for stone removal, and resection for cholangiocarcinoma.