Diagnosis of cholangiocarcinoma

Serum biochemistry is consistent with cholestatic jaundice. Bilirubin, alkaline phosphatase, and GGT levels may be very high. Their variations may reflect incomplete obstruction or initial involvement of only one hepatic duct.

Antimitochondrial antibodies are not detected in the serum, the level of a-FP is not elevated.

The feces are discolored, fatty, and often contain occult blood. There is no glucosuria.

Anemia is more pronounced than in ampullar carcinoma, but not due to blood loss; the reasons for this are unclear. The white blood cell count is at the upper limit of normal, with an elevated percentage of polymorphonuclear leukocytes.

Liver biopsy reveals signs of obstruction of large bile ducts. Tumor tissue cannot be obtained. Malignancy of the process is very difficult to confirm histologically.

It is important to perform cytological examination of tissues in the area of bile duct stricture. It is best to perform a brush biopsy during endoscopic or percutaneous interventions or a puncture biopsy under ultrasound or X-ray control. Tumor cells are detected in 60-70% of cases. Examination of bile aspirated directly during cholangiography is of much less importance.

In some cases, the level of the tumor marker CA19/9 increases with cholangiocarcinoma, but there are reports of high levels of this marker also in benign diseases, which reduces its significance for screening studies. Simultaneous determination of CA19/9 and carcinoembryonic antigen may be more accurate.

Scanning

Ultrasound is especially important, as it allows for the detection of dilation of the intrahepatic ducts. The tumor can be detected in 40% of cases. Ultrasound (in real time, in combination with Doppler examination) accurately detects portal vein tumor involvement, both occlusion and wall infiltration, but is less suitable for detecting hepatic artery involvement. Endoscopic intraductal ultrasound remains an experimental method, but it can provide important information about the spread of the tumor within and around the bile duct.

CT reveals dilatation of the intrahepatic bile ducts, but the tumor, the density of which does not differ from the density of the liver, is more difficult to visualize. CT allows you to identify lobar atrophy and the relative position of the caudate lobe and the tumor in the porta hepatis area. The modern method of spiral CT with computer reconstruction allows you to accurately determine the anatomical relationships of the vessels and bile ducts in the porta hepatis.

MRI can detect larger intrahepatic (cholangiocellular) carcinomas, but in extrahepatic tumors MRI has no additional advantage over ultrasound or CT. Some centers perform magnetic resonance cholangiography with bile duct (and pancreatic) reconstruction, which can be a very valuable diagnostic tool.

Cholangiography

Endoscopic or percutaneous cholangiography or a combination of both are of great diagnostic value and should be performed in all patients with clinical signs of cholestasis and signs of intrahepatic bile duct dilation detected by ultrasound or CT.

The tumor can be detected by cytological examination or transpapillary forceps biopsy during ERCP.

Endoscopic retrograde cholangiography reveals a normal common bile duct and gallbladder, as well as obstruction in the region of the porta hepatis.

Percutaneous cholangiography. Obstruction appears as a sharp rupture of the duct or as a nipple. The intrahepatic bile ducts are dilated in all cases. If obstruction develops only in the right or left hepatic duct, puncture of both ducts may be required for its precise localization.

Angiography

Digital subtraction angiography can visualize the hepatic artery and portal vein, as well as their intrahepatic branches. This method remains of great importance for preoperative assessment of tumor resectability.

With increasing cholestatic jaundice, the most likely clinical diagnosis is periampullary carcinoma. In addition, drug-induced jaundice, primary sclerosing cholangitis, and primary biliary cirrhosis are possible. Although such a course is not typical for cholangiocarcinoma, it should be excluded in a systematic diagnostic search. Data from the anamnesis and objective examination are usually of little help in diagnosis.

The first stage of examination for cholestasis is ultrasound. In cholangiocarcinoma, dilation of the intrahepatic bile ducts is detected. The common bile duct may be unchanged, the changes may be questionable, or dilation of the duct below the extrahepatic tumor is possible. To establish the level and parameters of the stricture, percutaneous or endoscopic cholangiography, cytological examination and biopsy are performed.

Sometimes patients with cholestasis are referred for surgery without cholangiography because the cause of the obstruction, pancreatic carcinoma or stones, is determined by other imaging techniques. If the common bile duct is normal, palpation of the porta hepatis area reveals no abnormalities, and the cholangiogram (without filling the intrahepatic bile ducts) is normal, the diagnosis is questionable. The mass in the porta hepatis area is too high and too small to be detected. Signs such as an enlarged green liver and a collapsed gallbladder should be given due consideration.

If the ultrasound examination of a patient with cholestasis does not reveal bile duct dilation, other possible causes of cholestasis should be considered, including drug-induced jaundice (history) and primary biliary cirrhosis (antimitochondrial antibodies). Histological examination of liver tissue is useful. If primary sclerosing cholangitis is suspected, cholangiography is the mainstay of diagnosis. In all patients with cholestasis without bile duct dilation, in whom the diagnosis is unclear, ERCP should be performed.

Scanning and cholangiography can diagnose bile duct stricture due to cholangiocarcinoma. In cases of hilus lesions, differential diagnosis is made between lymph node metastasis, cystic duct carcinoma, and periampullary pancreatic carcinoma, taking into account the history and other imaging findings.

Tumor staging

If the patient's condition allows for surgery, the resectability and size of the tumor should be assessed. Metastases, which are usually late, should be identified.

Lesions of the lower and middle sections of the common bile duct are usually amenable to resection, although angiography and venography should be performed to exclude vascular invasion.

The more common cholangiocarcinoma of the portal of the liver is more problematic. If cholangiography shows involvement of the second-order hepatic ducts of both lobes of the liver (type IV) or angiography shows tumor extension around the main trunk of the portal vein or hepatic artery, the tumor is unresectable. In these cases, palliative intervention is indicated.

If the tumor is limited to the bile duct bifurcation, affects only one lobe of the liver, or compresses a branch of the portal vein or hepatic artery on the same side, resection is possible. Preoperative imaging studies are necessary to determine whether the liver will remain viable after resection. The remaining liver segment should have a large enough duct that can be anastomosed with the intestine, an intact branch of the portal vein and hepatic artery. During surgery, additional ultrasound and examination are performed to exclude lymph node involvement.

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