[Imaging of peripheral cholangiocarcinoma. Comparison with pathological anatomy]

Peripheral cholangiocarcinoma is a rare malignant intrahepatic tumor which originates in the distal bile duct. Our purpose was to identify the imaging characteristics of peripheral cholangiocarcinoma and to establish a correlation with surgical and histopathologic findings.

The imaging data of 16 patients with proven cholangiocarcinoma were retrospectively reviewed by sonography in 13 cases, computed tomography in 13 cases, magnetic resonance imaging in 6 cases, and angiography in 10 cases and correlated with surgical and histopathologic findings.

In most cases peripheral cholangiocarcinoma appeared as a single, large (> 10 cm), heterogeneous, and non encapsulated mass. On precontrast computed tomography, the lesions were mostly low density. Enhancement was moderate in the bolus phase and increased in the delayed scan. With magnetic resonance imaging, lesion signals were low intensity in T1-weighted images and variable intensity in T2-weighted images. On angiogram, lesions were often hypovascular. Associated features were frequently observed: portal encasement (69%), lobar atrophy or capsular retraction (43%), dilated intrahepatic bile ducts (30%), extension into the hepatic capsule (23%), and inferior vena cava extension (15%). Radiopathologic comparison showed that imaging modalities accurately identified vascular encasement, but underestimated extrahepatic tumor extension.

In most cases, peripheral cholangiocarcinoma has a typical appearance which may be helpful in differentiating this disease from other intrahepatic tumors.