Discussion: Cholangiocarcinomas are rare slow-growing malignancies of the biliary duct system, that may occur anywhere within the biliary system from the liver to the ampulla of Vater. Cholangiocarcinomas are encountered in 3 geographic regions: intrahepatic, extrahepatic (ie, perihilar), and distal extrahepatic. Perihilar tumors are the most common and intrahepatic tumors are the least common. Perihilar tumors also called Klatskin tumors occur at the bifurcation of right and left hepatic ducts. 95% of these tumors are ductal adenocarcinomas and the remainder are squamous cell tumors. Local extension occurs into the liver, porta hepatis, and regional lymph nodes of the celiac and pancreaticoduodenal chains. The etiology of most bile duct cancers remains undetermined. Long-standing inflammation, as with primary sclerosing cholangitis (PSC) or chronic parasitic infection, has been suggested as playing a role by inducing hyperplasia, cellular proliferation, and, ultimately, malignant transformation. Cholangiocarcinomas is slow growing and tends to invade locally dissecting along tissue planes. In Southeast Asia, chronic infection with liver flukes, Clonorchis sinensis has been causally related to cholangiocarcinomas. It also has an association with ulcerative colitis and primary sclerosing cholangitis. Increased incidence has been noted in exposure to Thortrast radiopaque medium and in rubber industries. Several congenital diseases also show a relationship, including choledochal cysts and Caroli’s disease.
Clinical presentation:
Patients often present with painless jaundice and many patients present with unresectable or metastatic disease. Pruritis and non-specific abdominal pain are other common complaints. Physical exam findings include hepatomegaly (tender/non-tender), a palpable non-tender gallbladder (Courvoisier sign) and splenomegaly secondary to portal hypertension. Lab findings include elevated LFT’s. CEA and CA 19-9 tumor markers may be positive but cholangiocarcinomas does not produce alpha feto proteins (AFP).
Imaging:
Initial evaluation should be with ultrasound and CT. The most common US finding is general ductal dilitation. Focal ductal dilitation, lobar atrophy, bile duct wall thickening and rarely a polypoid mass within the ducts may also be seen. CT demonstrates biliary dilation as well but can show thickening of the bile duct walls more accurately. In peripheral cholangiocarcinomas the CT scan is often nonspecific demonstrating minimal contrast enhancement with a poorly defined isoattenuating or hypoattenuating mass. Delayed enhancement (8-10 min) is useful in hilar tumors. The tumor itself is only identified in about 50% of cases. CT is good at showing lymphadenopathy and lobar atrophy. Cholangiography(ERCP or PTC) is very helpful in demonstrating ductal anatomy and has the added benefit of enabling stent placement for drainage. MRI Cholangiography is being used more frequently and may help define tumor extension into portal vessels.
Treatment:
Stenting is very useful in both palliative care to relieve obstruction and for symptomatic relief preop. The only possible cure is complete resection but imaging confirmation of complete resection is often impossible. Lesions are considered unresectable if tumor involves either both lobes of the liver or major portal veins or hepatic arteries. Overall resecatability is about 40%. Chemo and radiation therapy can be used for palliative treatment but show little benefit. Celiac-plexus block via regional injection of alcohol or other sclerosing agent can relieve pain in the mid-back associated with retroperitoneal tumor growth.
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