The bile ducts connect the liver to the intestine and their function is to drain the bile, a waste product of normally functioning liver cells, which are also called hepatocytes. Diseases of the bile ducts usually result in narrowing of the duct, which is called a stricture. 
Strictures can be characterized as:

• Scarring (primary sclerosing cholangitis, secondary sclerosing cholangitis) 
• Traumatic (usually surgical injury) 
• Stone forming 
• Neoplastic (cancerous growths or tumors and polyps). 

Jaundice or abnormal liver enzyme blood tests are the most common reasons physicians would suspect a problem with the bile ducts. 
  Bile duct cancer is called cholangiocarcinoma. It arises from the epithelium or biliary tree lining either within the liver or in ducts located outside of the liver. Cholangiocarcinoma is difficult to cure and many cases are sporadic with no identifiable etiology or cause.
Risk factors associated with cholangiocarcinoma include:

• Primary sclerosing cholangitis (PSC) 
• Ulcerative colitis  
• Liver fluke infestations 
• Chronic cholestasis with chronic stone disease 
• Congenital biliary cystic anomalies 

Cancer staging is the process health professionals use to determine where cancer may have spread. It is used to find out if the cancer stayed in the bile ducts or worked its way to the lymph nodes or to other parts of the body. 
Current methods of staging cholangiocarcinoma include:

• Computed tomography (CT) 
• Magnetic resonance imaging (MRI) 
• Endoscopic retrograde cholangiopancreatography (ERCP) 
• Endoscopic ultrasound (EUS) 

Each method has advantages and limitations. A combination of tests can select candidates for surgical resection, which affords long-term survival in a minority of patients. 
  Relief of biliary obstruction is the most accepted treatment approach for most patients with cholangiocarcinoma. Stents are useful in providing adequate draining of the bile ducts.
Two types of stents are employed:

• Endoscopic stents administered with the use of an endoscope or a slender, tubular optical instrument 
• Percutaneous stents administered through the skin 

The best approach is dependent upon patient characteristics, location of the tumor and physician expertise. 
Photodynamic therapy may have a role in selected patients not well palliated or relieved by routine stents based on preliminary trials.
  Interpretation of the available, limited data that exists suggests a small survival advantage of chemotherapy and radiation for cholangiocarcinoma. 
  Liver transplantation is currently an effective method of treatment for cholangiocarcinoma of the hilum of the liver in patient who cannot undergo surgical resection.  Patients who are eligible for this protocol at Cleveland Clinic undergo chemotherapy and radiation therapy followed by liver transplantation.  Long-term survival following this treatment protocol is similar to survival following liver transplantation for other conditions.