Cholangiocarcinoma, also known as bile duct cancer, is a type of cancer that forms in the bile ducts. Symptoms of cholangiocarcinoma may include abdominal pain, yellowish skin, weight loss, generalized itching, and fever. Light colored stool or dark urine may also occur. Cholangiocarcinoma is typically incurable at diagnosis. In these cases palliative treatments may include surgical resection, chemotherapy, radiation therapy, and stenting procedures. In about a third of cases involving the common bile duct and less commonly with other locations the tumor can be completely removed by surgery offering a chance of a cure.

The most common physical indications of cholangiocarcinoma are abnormal liver function tests, jaundice (yellowing of the eyes and skin occurring when bile ducts are blocked by tumor), abdominal pain (30–50%), generalized itching (66%), weight loss (30–50%), fever (up to 20%), and changes in the color of stool or urine. To some extent, the symptoms depend upon the location of the tumor: people with cholangiocarcinoma in the extrahepatic bile ducts (outside the liver) are more likely to have jaundice, while those with tumors of the bile ducts within the liver more often have pain without jaundice.

Certain parasitic liver diseases may be risk factors as well. Colonization with the liver flukes Opisthorchis viverrini (found in Thailand, Laos PDR, and Vietnam) or Clonorchis sinensis (found in China, Taiwan, eastern Russia, Korea, and Vietnam) has been associated with the development of cholangiocarcinoma. Control programs aimed at discouraging the consumption of raw and undercooked food have been successful at reducing the incidence of cholangiocarcinoma in some countries. People with chronic liver disease, whether in the form of viral hepatitis (e.g. hepatitis B or hepatitis C), alcoholic liver disease, or cirrhosis of the liver due to other causes, are at significantly increased risk of cholangiocarcinoma.

Cholangiocarcinoma can affect any area of the bile ducts, either within or outside the liver. Tumors occurring in the bile ducts within the liver are referred to as intrahepatic, those occurring in the ducts outside the liver are extrahepatic, and tumors occurring at the site where the bile ducts exit the liver may be referred to as perihilar. A cholangiocarcinoma occurring at the junction where the left and right hepatic ducts meet to form the common hepatic duct may be referred to eponymously as a Klatskin tumor. Histologically, cholangiocarcinomas may vary from undifferentiated to well-differentiated. They are often surrounded by a brisk fibrotic or desmoplastic tissue response; in the presence of extensive fibrosis, it can be difficult to distinguish well-differentiated cholangiocarcinoma from normal reactive epithelium.

Ultrasound of the liver and biliary tree is often used as the initial imaging modality in people with suspected obstructive jaundice. Ultrasound can identify obstruction and ductal dilatation and, in some cases, may be sufficient to diagnose cholangiocarcinoma. Computed tomography (CT) scanning may also play an important role in the diagnosis of cholangiocarcinoma.

Regards
Amalia
Managing Editor
Journal of Clinical Oncology and Cancer Research.