CT and MRI features of cholangiocarcinoma
What is cholangiocarcinoma, and what are its CT and MR imaging features?
Cholangiocarcinoma is the second most common primary hepatic malignancy, is more common in women than in men, usually occurs in patients who are >50 years of age, and is most often due to adenocarcinoma. It can be intrahepatic (10%), hilar (60%), or extrahepatic (30%) in location.
Intrahepatic cholangiocarcinoma presents as a masslike infiltrative hepatic lesion on CT and MRI that typically demonstrates heterogeneous mild to moderate arterial phase enhancement, peripheral venous or delayed phase washout, delayed phase central enhancement (secondary to extensive intratumoral fibrosis), and hypointense signal intensity relative to liver parenchyma on hepatobiliary phase images. Compared with HCC, vascular invasion is less commonly seen. However, segmental or lobar intrahepatic bile duct dilation and associated hepatic parenchymal atrophy are more commonly seen in the setting of cholangiocarcinoma.
Hilar cholangiocarcinoma, also known as Klatskin tumor, tends to present with biliary strictures involving the right hepatic duct, the left hepatic duct, or bifurcation of the CHD, secondary to periductal tumor infiltration and extensive fibrosis associated with this tumor. The tumor is often difficult to visualize owing to its superficial spread but may appear either as a focal enhancing bile duct mass (when exophytic or polypoid intraluminal in configuration) or as a focal enhancing region of bile duct wall thickening with associated luminal narrowing. Associated upstream bile duct dilation may be present. Heterogeneous perfusional changes or atrophy involving a segment or lobe of the liver may also be seen. Regional lymphadenopathy or distant metastatic disease may also be encountered.
Extrahepatic cholangiocarcinoma involves the CHD or CBD and demonstrates similar imaging features to those of hilar cholangiocarcinoma