Endoscopic Ultrasound for the Diagnosis and Staging of Biliary Malignancy.

Cholangiocarcinoma (CCA) is the most common neoplasm of the biliary tract. The biological behavior and prognosis of CCA vary depending on the tumor's location in the biliary tree, dictating a different diagnostic, and treatment approach. Establishing a diagnosis of CCA remains a challenge and up to 20% of biliary strictures can yield indeterminate results, despite extensive evaluation. Endoscopic ultrasound (EUS) has become an effective diagnostic tool, as it provides high-quality images of the bile duct and allows for the sampling of strictures in the same plane of view. In this chapter, we explore the utility of EUS as a diagnostic and staging tool for biliary cancers.