Hilar biliary obstruction: malignant masquerades.

Biliary obstruction at the hepatic hilus is most often due to malignancy. Clinically, it can be very difficult to differentiate malignant from benign obstruction when a mass lesion is not evident on cross-sectional imaging. In this article, we describe three cases of benign biliary obstruction due to so-called malignant masquerades to familiarize the reader with the clinical, radiographic, and pathological features of these uncommon but important entities.