The bile duct is a system of tubes that connect the gallbladder to the liver, pancreas, and small intestine. Quite commonly, the bile ducts will develop benign conditions, such as gallstones or adenomas. Very rarely, however, they grow cancerous tumours called cholangiocarcinomas.
This type of cancer grows out of the cells lining the bile ducts and can be intrahepatic or extrahepatic; that is, it can grow in the bile ducts within the liver or in those outside the liver. Intrahepatic bile duct cancer makes up about 10 percent of all bile duct cancers, and it is less common than extrahepatic bile duct cancer.
Risk factors for this type of cancer include: hepatitis C infection, parasitic infections (such as a liver fluke), bile duct stones, liver cirrhosis, and primary sclerosing cholangitis. 
Cholangiocarcinoma does not present noticeable symptoms in its early stages. Symptoms will appear when the tumour has invaded the liver or other surrounding organs, causing changes to normal function. Jaundice is the most common symptom, making the skin, whites of the eyes, and stools appear yellowish. Other signs and symptoms can include loss of appetite, weight loss, fever, nausea and vomiting, and abdominal pain.
Diagnosis is made using a battery of tests, which may include:
- Blood tests: to determine gallbladder function and detect tumour markers (such as CEA and CA 19-9).
- Imaging tests: X-rays, MRI, and ultrasound can be used to distinguish between benign and cancerous conditions.
- Imaging-guided biopsy.
- Endoscopic or laparoscopic ultrasound: to see how far the tumour has grown or spread, which can help in planning for surgery.
- An endoscopic retrograde cholangiopancreatography (ERCP): when extrahepatic bile duct cancer is suspected, this can confirm if the bile duct is blocked or not.
- With this technique, the specialist looks inside the bile ducts using a flexible tube with a light and lens on the end (endoscope).
- A percutaneous transhepatic cholangiography (PTC): X-ray of the bile ducts and liver that uses a contrast dye to enhance the different tissues.
- This technique is used to find any blockages, to see if the tumour has spread to other organs, and to take a biopsy to determine the tumour type and stage.
- Laparoscopy and laparotomy: gain a direct view of the structures around the bile duct and plan for treatment.
Treatment for cholangiocarcinoma will depend on the stage the tumour is in, whether it can be removed completely, and the overall health of the patient. Treatment options include surgery, radiation, and chemotherapy. Surgery can be done to remove the part of the bile duct affected or to resect part of the liver. Total resection of the liver (hepatectomy) is followed by a liver transplant.
Traditionally, liver transplantation has been contraindicated for cholangiocarcinoma. However, more recently, studies have looked at intrehepatic cholangiocarcinoma patients who received a transplant following a misdiagnosis of HCC (hepatocellular carcinoma or liver cancer) and found that these patients have shown encouraging results.