Review of endoscopic techniques in the diagnosis and management of cholangiocarcinoma

TOPIC HIGHLIGHTtumors are least common [1] .The Bismuth classification is used to describe the biliary tract involvement and is helpful in planning surgical intervention.TypeⅠtumors are found below the bifurcation of the left and right hepatic ducts.Type Ⅱ tumors involve the bifurcation.Type Ⅲa and Ⅲb tumors occlude the common hepatic duct and either the right or left hepatic duct, respectively.Type Ⅳ tumors are multicentric, or they involve the bifurcation and both the right and left hepatic ducts (Figure 1).The incidence rates for cholangiocarcinomas vary depending on geographic location with the highest rates found in Southeast Asia.In the United States, between 4000 and 5000 cases are found annually.For unknown reason, the incidence of and mortality rates for intrahepatic cholangiocarcinomas have been increasing in recent years while the incidence of extrahepatic cholangiocarcinomas have been decreasing [2] .Accurate knowledge of tumor extent and anatomy as well as obtaining a tissue diagnosis is important in determining therapeutic options.In this article, we will review the endoscopic modalities available in the diagnosis and management of cholangiocarcinomas. DiagnosisThe etiology of biliary strictures can often be difficult to establish.The differential diagnosis of biliary strictures is extensive and includes, but is not limited to, primary sclerosing cholangitis, gallbladder carcinoma, pancreatic carcinoma, intraductal papillary mucinous tumor, or benign biliary strictures from causes such as pancreatitis.Cholangiocarcinomas often pose a diagnostic challenge due to difficulties in obtaining an adequate specimen for cytology.Tissue diagnosis is important in certain subgroups of patients such as those who are borderline surgical candidates, those with indeterminate strictures (e.g.patients with primary sclerosing cholangitis), or before chemotherapy and radiation therapy. Magnetic resonance cholangiopancreatographyMagnetic resonance cholangiopancreatography (MRCP) can be a useful noninvasive adjunct to current techniques.It has the ability to define the proximal and distal extent of strictures as well as to evaluate for any intrahepatic mass lesion.One series evaluated the role of MRCP in patients with bile duct obstruction.Of 126 patients, 14 had bile duct malignancy.Of those 14, 12 patients were diagnosed by MRCP, with a sensitivity of 86% and specificity of 98% [3] .Another study by Rosch et al [4] had lower specificity for malignant obstructions.