Cholangiocarcinoma, also known as bile duct cancer, is a form of cancer that is composed of mutated epithelial cells (or cells showing characteristics of epithelial differentiation) that originate in the bile ducts which drain bile from the liver into the small intestine. Other biliary tract cancers include gallbladder cancer and cancer of the ampulla of Vater.

Cholangiocarcinoma is a relatively rare neoplasm that is classified as an adenocarcinoma (a cancer that forms glands or secretes significant amounts of mucins). It has an annual incidence rate of 1–2 cases per 100,000 in the Western world, but rates of cholangiocarcinoma have been rising worldwide over the past few decades.

Prominent signs and symptoms of cholangiocarcinoma include abnormal liver function tests, abdominal pain, jaundice, and weight loss. Other symptoms such as generalized itching, fever, and changes in color of stool or urine may also occur. The disease is diagnosed through a combination of blood tests, imaging, endoscopy, and sometimes surgical exploration, with confirmation obtained after a pathologist examines cells from the tumor under a microscope. Known risk factors for cholangiocarcinoma include primary sclerosing cholangitis (an inflammatory disease of the bile ducts), infection with the parasitic liver flukes "Opisthorchis viverrini" or "Clonorchis sinensis", some congenital liver malformations, and exposure to Thorotrast (thorium dioxide), a chemical formerly used in medical imaging. However, most people with cholangiocarcinoma have no identifiable risk factors.

Cholangiocarcinoma is considered to be an incurable and rapidly lethal cancer unless both the primary tumor and any metastases can be fully removed by surgery. No potentially curative treatment exists except surgery, but most people have advanced stage disease at presentation and are inoperable at the time of diagnosis. People with cholangiocarcinoma are generally managed - though not cured - with chemotherapy, radiation therapy, and other palliative care measures. These are also used as additional therapies after surgery in cases where resection has apparently been successful (or nearly so).

A Klatskin tumor (or hilar cholangiocarcinoma) is a cholangiocarcinoma (cancer of the biliary tree) occurring at the confluence of the right and left hepatic bile ducts. It is named after Dr. Gerald Klatskin.

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: patients 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.

Blood tests of liver function in patients with cholangiocarcinoma often reveal a so-called "obstructive picture," with elevated bilirubin, alkaline phosphatase, and gamma glutamyl transferase levels, and relatively normal transaminase levels. Such laboratory findings suggest obstruction of the bile ducts, rather than inflammation or infection of the liver parenchyma, as the primary cause of the jaundice.

Periampullary cancer is a cancer that forms near the ampulla of Vater, an enlargement of the ducts from the liver and pancreas where they join and enter the small intestine.It consists of:

1. ampullary tumour from ampulla of Vater,

2. cancer of lower common bile duct, and

3. duodenal cancer adjacent to ampulla.

4. carcinoma head of pancreas

It presents with painless jaundice which may have waxing and waning nature because at times the sloughing of the tumor tissue relieves the obstruction partially.

Primary sclerosing cholangitis is typically classified into three subgroups based on whether the small and/or large bile ducts are affected. The subgroups of PSC include the following:

- Classic PSC

- Small-duct PSC

- PSC associated with autoimmune hepatitis

The cause of cholangiocarcinoma has not been clearly defined. A number of pathologic conditions, however, resulting in either acute or chronic biliary tract epithelial injury may predispose to malignant change. Primary sclerosing cholangitis, an idiopathic inflammatory condition of the biliary tree, has been clearly associated with the development of cholangiocarcinoma in up to 40% of patients. Congenital biliary cystic disease, such as choledochal cysts or Caroli's disease, has also been associated with malignant transformation in up to 25% of cases. These conditions appear to be related to an anomalous pancreatico-biliary duct junction and, perhaps, are related to the reflux of pancreatic secretions into the bile duct. Chronic biliary tract parasitic infection, seen commonly in Southeast Asia due to "Clonorchis sinensis" and "Opisthorchis viverrini", has also been identified as a risk factor. Although gallstones and cholecystectomy are not thought to be associated with an increased incidence of cholangiocarcinoma, hepatolithiasis and choledocholithiasis may predispose to malignant change. Further, industrial exposure to asbestos and nitrosamines, and the use of the radiologic contrast agent, Thorotrast (thorium dioxide), are considered to be risk factors for the development of cholangiocarcinoma.

Nearly half of people with PSC do not have symptoms and are often incidentally discovered to have PSC due to abnormal liver function tests, but a substantial proportion will have debilitating signs and symptoms of the disease. Signs and symptoms of PSC may include severe itching and non-specific fatigue. Yellowing of the skin and white portion of the eyes may also be seen. Enlargement of the liver and spleen are seen in approximately 40% of affected individuals. Abdominal pain affects about 20% of people with PSC.

Multiple episodes of life-threatening acute cholangitis (infection within the bile ducts) can be seen due to impaired drainage of the bile ducts, which increases the risk of infection.

- Dark urine due to excess conjugated bilirubin, which is water-soluble and excreted by the kidneys (i.e. choluria)

- Malabsorption, especially of fat, and steatorrhea (fatty stool), due to an inadequate amount of bile reaching the small intestine, leading to decreased levels of the fat-soluble vitamins, A, D, E and K.

- Portal hypertension, a complication of cirrhosis, which can manifest with esophageal and parastomal varices as well as hepatic encephalopathy (mental status alteration/disturbance caused by liver dysfunction and shunting of blood away from the scarred liver; such that ammonia detoxification is reduced with concomitant encephalopathy).

Murphy's sign is commonly negative on physical examination in choledocholithiasis, helping to distinguish it from cholecystitis. Jaundice of the skin or eyes is an important physical finding in biliary obstruction. Jaundice and/or clay-colored stool may raise suspicion of choledocholithiasis or even gallstone pancreatitis. If the above symptoms coincide with fever and chills, the diagnosis of ascending cholangitis may also be considered.

Greater than 70% of people with gallstones are asymptomatic and are found incidentally on ultrasound. Studies have shown that 10% of those people will develop symptoms within five years of diagnosis and 20% within 20 years.

The first symptoms typically include fever, intermittent abdominal pain, and hepatomegaly. Occasionally, jaundice occurs.

Morbidity is common and is caused by complications of cholangitis, sepsis, choledocholithiasis, and cholangiocarcinoma. These morbid conditions often prompt the diagnosis. Portal hypertension may be present, resulting in other conditions including splenomegaly, hematemesis, and melena. These problems can severely affect the patient's quality of life. In a 10-year period between 1995 and 2005, only 10 patients were surgically treated for Caroli disease, with an average patient age of 45.8 years.

After reviewing 46 cases of Caroli disease before 1990, 21.7% of the cases were the result of an intraheptic cyst or nonobstructive biliary tree dilation, 34.7% were linked with congenital hepatic fibrosis, 13% were isolated choledochal cystic dilation, and the remaining 24.6% had a combination of all three.

Because liver cancer is an umbrella term for many types of cancer, the signs and symptoms depend on what type of cancer is present. Cholangiocarcinoma is associated with sweating, jaundice, abdominal pain, weight loss and liver enlargement. Hepatocellular carcinoma is associated with abdominal mass, abdominal pain, emesis, anemia, back pain, jaundice, itching, weight loss and fever.

Initially, the symptoms of biliary atresia are indistinguishable from those of neonatal jaundice, a usually harmless condition commonly seen in infants. Distinctive symptoms of biliary atresia are usually evident between one and six weeks after birth. Infants and children with biliary atresia develop progressive cholestasis, a condition in which bile is unable to leave the liver and builds up inside of it. When the liver is unable to excrete bilirubin through the bile ducts in the form of bile, bilirubin begins to accumulate in the blood, causing symptoms. These symptoms include yellowing of the skin, itchiness, poor absorption of nutrients (causing delays in growth), pale stools, dark urine, and a swollen abdomen. Eventually, cirrhosis with portal hypertension will develop. If left untreated, biliary atresia can lead to liver failure. Unlike other forms of jaundice, however, biliary-atresia-related cholestasis mostly does not result in kernicterus, a form of brain damage resulting from liver dysfunction. This is because in biliary atresia, the liver, although diseased, is still able to conjugate bilirubin, and conjugated bilirubin is unable to cross the blood–brain barrier.

Gallstones may be asymptomatic, even for years. These gallstones are called "silent stones" and do not require treatment. The size and number of gallstones present does not appear to influence whether people are symptomatic or asymptomatic. A characteristic symptom of gallstones is a gallstone attack, in which a person may experience colicky pain in the upper-right side of the abdomen, often accompanied by nausea and vomiting, that steadily increases for approximately 30 minutes to several hours. A person may also experience referred pain between the shoulder blades or below the right shoulder. These symptoms may resemble those of a "kidney stone attack". Often, attacks occur after a particularly fatty meal and almost always happen at night, and after drinking.

In addition to pain, nausea, and vomiting, a person may experience a fever. If the stones block the duct and cause bilirubin to leak into the bloodstream and surrounding tissue, there may also be jaundice and itching. This can also lead to confusion. If this is the case, the liver enzymes are likely to be raised.

Common bile duct stone, also known as choledocholithiasis, is the presence of gallstones in the common bile duct (thus "" + ""). This condition causes jaundice and liver cell damage. Treatment is by cholecystectomy and ERCP.

Early symptoms mimic gallbladder inflammation due to gallstones. Later, the symptoms may be that of biliary and stomach obstruction.

Of note, Courvoisier's law states that in the presence of a palpably enlarged gallbladder which is nontender and accompanied with mild painless jaundice, the cause is unlikely to be gallstones. This implicates possible malignancy of the gallbladder or pancreas, and the swelling is unlikely due to gallstones due to the chronic inflammation association with gallstones leading to a shunken, non-distensible gallbladder. However, Ludwig Georg Courvoisier's original observations, published in Germany in 1890, were not originally cited as a 'law', and no mention of malignancy or pain (tenderness) was made. These points are commonly missquoted or confused in the medical literature.

Cholestasis is a condition where bile cannot flow from the liver to the duodenum. The two basic distinctions are an obstructive type of cholestasis where there is a mechanical blockage in the duct system that can occur from a gallstone or malignancy, and metabolic types of cholestasis which are disturbances in bile formation that can occur because of genetic defects or acquired as a side effect of many medications.

Caroli disease (communicating cavernous ectasia, or congenital cystic dilatation of the intrahepatic biliary tree) is a rare inherited disorder characterized by cystic dilatation (or ectasia) of the bile ducts within the liver. There are two patterns of Caroli disease: focal or simple Caroli disease consists of abnormally widened bile ducts affecting an isolated portion of liver. The second form is more diffuse, and when associated with portal hypertension and congenital hepatic fibrosis, is often referred to as "Caroli syndrome." The underlying differences between the two types are not well understood. Caroli disease is also associated with liver failure and polycystic kidney disease. The disease affects about one in 1,000,000 people, with more reported cases of Caroli syndrome than of Caroli disease.

Caroli disease is distinct from other diseases that cause ductal dilatation caused by obstruction, in that it is not one of the many choledochal cyst derivatives.

The most frequent liver cancer, accounting for approximately 75% of all primary liver cancers, is hepatocellular carcinoma (HCC) (also named "hepatoma", which is a misnomer because adenomas are usually benign). HCC is a cancer formed by liver cells, known as hepatocytes, that become malignant. Another type of cancer formed by liver cells is hepatoblastoma, which is specifically formed by immature liver cells. It is a rare malignant tumor that primarily develops in children, and accounts for approximately 1% of all cancers in children and 79% of all primary liver cancers under the age of 15. Most hepatoblastomas form in the right lobe.

Liver cancer can also form from other structures within the liver such as the bile duct, blood vessels and immune cells. Cancer of the bile duct (cholangiocarcinoma and cholangiocellular cystadenocarcinoma) account for approximately 6% of primary liver cancers. There is also a variant type of HCC that consists of both HCC and cholangiocarcinoma. Tumors of the blood vessels (angiosarcoma and hemangioendothelioma, embryonal sarcoma and fibrosarcoma are produced from a type of connective tissue known as mesenchyme. Cancers produced from muscle in the liver are leiomyosarcoma and rhabdomyosarcoma. Other less common liver cancers include carcinosarcomas, teratomas, yolk sac tumours, carcinoid tumours and lymphomas. Lymphomas usually have diffuse infiltration to liver, but It may also form a liver mass in rare occasions.

Many cancers found in the liver are not true liver cancers, but are cancers from other sites in the body that have spread to the liver (known as metastases). Frequently, the site of origin is the gastrointestinal tract, since the liver is close to many of these metabolically active, blood-rich organs near to blood vessels and lymph nodes (such as pancreatic cancer, stomach cancer, colon cancer and carcinoid tumors mainly of the appendix), but also from breast cancer, ovarian cancer, lung cancer, renal cancer, prostate cancer.

A person with cholangitis may complain of abdominal pain (particularly in the right upper quadrant of the abdomen), fever, rigors (uncontrollable shaking) and a feeling of uneasiness (malaise). Some may report jaundice (yellow discoloration of the skin and the whites of the eyes).

Physical examination findings typically include jaundice and right upper quadrant tenderness. Charcot's triad is a set of three common findings in cholangitis: abdominal pain, jaundice, and fever. This was assumed in the past to be present in 50–70% of cases, although more recently the frequency has been reported as 15–20%. Reynolds' pentad includes the findings of Charcot's triad with the presence of septic shock and mental confusion. This combination of symptoms indicates worsening of the condition and the development of sepsis, and is seen less commonly still.

In the elderly, the presentation may be atypical; they may directly collapse due to sepsis without first showing typical features. Those with an indwelling stent in the bile duct (see below) may not develop jaundice.

Patients are usually asymptomatic at diagnosis. As a result, disease is often advanced at diagnosis.

Gallstone disease refers to the condition where gallstones are either in the gallbladder or common bile duct. The presence of stones in the gallbladder is referred to as cholelithiasis, from the Greek "chol"- (bile) + "lith"- (stone) + -"iasis" (process). If gallstones migrate into the ducts of the biliary tract, the condition is referred to as choledocholithiasis, from the Greek "chol"- (bile) + "docho"- (duct) + "lith"- (stone) + "iasis"- (process). Choledocholithiasis is frequently associated with obstruction of the biliary tree, which in turn can lead to acute ascending cholangitis, from the Greek: "chol"- (bile) + "ang"- (vessel) + "itis"- (inflammation), a serious infection of the bile ducts. Gallstones within the ampulla of Vater can obstruct the exocrine system of the pancreas, which in turn can result in pancreatitis.

Other common manifestations of the disease include: weakness and tiring easily; dry mouth; sleep problems; and a palpable abdominal mass."

Symptoms having to do with hepatomegaly can include several, among them the individual may experience some weight loss, poor appetite and lethargy (jaundice and bruising may also be present)

Since pancreatic cancer usually does not cause recognizable symptoms in its early stages, the disease is typically not diagnosed until it has spread beyond the pancreas itself. This is one of the main reasons for the generally poor survival rates. Exceptions to this are the functioning PanNETs, where over-production of various active hormones can give rise to symptoms (which depend on the type of hormone).

Bearing in mind that the disease is rarely diagnosed before the age of 40, common symptoms of pancreatic adenocarcinoma occurring before diagnosis include:

- Pain in the upper abdomen or back, often spreading from around the stomach to the back. The location of the pain can indicate the part of the pancreas where a tumor is located. The pain may be worse at night and may increase over time to become severe and unremitting. It may be slightly relieved by bending forward. In the UK, about half of new cases of pancreatic cancer are diagnosed following a visit to a hospital emergency department for pain or jaundice. In up to two-thirds of people abdominal pain is the main symptom, for 46% of the total accompanied by jaundice, with 13% having jaundice without pain.

- Jaundice, a yellow tint to the whites of the eyes or skin, with or without pain, and possibly in combination with darkened urine. This results when a cancer in the head of the pancreas obstructs the common bile duct as it runs through the pancreas.

- Unexplained weight loss, either from loss of appetite, or loss of exocrine function resulting in poor digestion.

- The tumor may compress neighboring organs, disrupting digestive processes and making it difficult for the stomach to empty, which may cause nausea and a feeling of fullness. The undigested fat leads to foul-smelling, fatty feces that are difficult to flush away. Constipation is common.

- At least 50% of people with pancreatic adenocarcinoma have diabetes at the time of diagnosis. While long-standing diabetes is a known risk factor for pancreatic cancer (see Risk factors), the cancer can itself cause diabetes, in which case recent onset of diabetes could be considered an early sign of the disease. People over 50 who develop diabetes have eight times the usual risk of developing pancreatic adenocarcinoma within three years, after which the relative risk declines.

At CT scans, bile duct hamartomas appear as small, well-defined hypo- or isoattenuating masses with little or no enhancement after contrast administration. At MRI, they appear hypointense on T1-weighted images, iso- or slightly hyperintense on T2-weighted images, and hypointense after administration of gadolinium based contrast-agent. On imaging, multiple hamartomas may look similar to metastases or microabscesses.

Mirizzi's syndrome has no consistent or unique clinical features that distinguish it from other more common forms of obstructive jaundice. Symptoms of recurrent cholangitis, jaundice, right upper quadrant pain, and elevated bilirubin and alkaline phosphatase may or may not be present. Acute presentations of the syndrome include symptoms consistent with cholecystitis.

Surgery is extremely difficult as Calot's triangle is often completely obliterated and the risks of causing injury to the CBD are high.