Peripheral (Intrahepatic) Cholangiocarcinoma

 Most common type of CCA


image Well circumscribed, large, with lobulated margins

image Multicentricity, especially around main tumor


• Periductal-infiltrating CCA
image Grows along bile ducts and is elongated, spiculated, or branch-like

• Progressive, gradual, and concentric filling (centripetal) on delayed phase images
image Usually not isodense to vessels (unlike hemangioma)

• Substantial delayed enhancement (i.e., greater than that of liver parenchyma) is common (74%)
image Attributed to fibrous stroma in CCA

• ± capsular retraction (frequent), with parenchymal atrophy of liver segments peripheral to tumor

• Bile ducts will be dilated upstream from tumor
image Duct lining may be thickened and enhanced

image Rare with other types of hepatic tumors




TOP DIFFERENTIAL DIAGNOSES




• Hepatic metastases and lymphoma

• Hepatocellular carcinoma

• Focal confluent fibrosis


PATHOLOGY




• Based on growth characteristics
image Mass forming (exophytic/nodular); most common form

image Periductal infiltrating (sclerosing)

image Intraductal growing (polypoid/papillary)


CLINICAL ISSUES




• Only minority of cholangiocarcinomas are peripheral type

• Large size at presentation contributes to poor prognosis

image
(Left) Intrahepatic cholangiocarcinomas generally arise in noncirrhotic livers. This gross photograph shows a white-tan, firm, and distinct mass in a background of noncirrhotic liver. (Courtesy M. Yeh, MD, PhD.)


image
(Right) Desmoplastic stroma is a common finding in intrahepatic cholangiocarcinoma. (Courtesy M. Yeh, MD, PhD.)

image
(Left) Axial CECT of a 46-year-old woman with jaundice shows the portal vein image and bile ducts image encased and obstructed by the tumor image, accounting for the altered perfusion of the right hepatic lobe. Hepatic veins were encased as well, resulting in collateral blood vessels seen within the right lobe image.


image
(Right) Axial 10-minute delayed CECT in the same patient shows heterogeneous, persistent enhancement of the tumor image, a feature of cholangiocarcinoma (and other tumors with fibrous stroma).


TERMINOLOGY


Abbreviations




• Cholangiocarcinoma (CCA)


Synonyms




• Cholangiocellular carcinoma, intrahepatic cholangiocarcinoma


Definitions




• CCA: Adenocarcinoma arising from bile duct epithelium (cholangiocytes)

• Peripheral CCA: Tumor arising from intrahepatic bile ducts


IMAGING


General Features




• Best diagnostic clue
image Infiltrative hepatic mass with capsular retraction and delayed persistent enhancement (CECT and MR)

• Location
image Originates from interlobular bile ducts (i.e., bile ducts distal to 2nd order branches)

• Size
image Usually large (> 5 cm) at diagnosis

• Morphology
image Peripheral CCA is usually a mass-forming tumor
– Often has “satellite” nodules

• Key concepts
image Mass-forming CCA: Well circumscribed, large, with lobulated margins
– Multicentricity, especially around main tumor

image Periductal-infiltrating CCA: Grows along bile ducts and is elongated, spiculated, or branch-like

image Intraductal-growing CCA: Small, sessile, or polypoid
– Often spreading superficially along mucosal surface and resulting in multiple tumors (papillomatosis) along various segments of bile ducts


CT Findings




• NECT
image Well-defined, predominantly homogeneous, hypodense mass
– Lobular margins

– Hypodense satellite nodules (65% of CCAs)

– Punctate, stippled, chunky calcifications (18% of CCAs)

• CECT
image Mass-forming PCC
– Thin or thick rim-like enhancement frequently seen around periphery of tumor on arterial phase images

– Progressive, gradual, and concentric filling (centripetal) on delayed phase images
image Usually not isodense to vessels (unlike hemangioma)

– Substantial delayed enhancement (i.e., > that of liver parenchyma) is common (74%)
image Attributed to fibrous stroma in CCA

– Homogeneous or heterogeneous hyperattenuating enhancement
image Entire mass may be enhanced only on delayed-phase images

image May be only evidence of tumor

– ± capsular retraction (frequent), with parenchymal atrophy of liver segments peripheral to tumor

image Bile ducts will be dilated upstream from tumor
– May not be evident in very peripheral CCA

– Duct lining may be thickened and enhanced
image Rare for hepatic metastases or other hepatic primary tumors


MR Findings




• T1WI
image Heterogeneous hypointense mass

• T2WI
image Hyperintense periphery (cellular tumor) + large central hypointensity (fibrosis)

image Hyperintense foci in center may represent necrosis, mucin

• T1WI C+
image Central hypointense areas exhibit homogeneous, heterogeneous, or no enhancement
– Regions of fibrosis display enhancement (delayed) while those of coagulative necrosis and mucin show no enhancement

image Dynamic MR: Minimal or moderate rim enhancement and progressive and concentric filling with contrast material
– Intratumoral fibrous stroma displays marked or prolonged enhancement on delayed phase scans

– Some cases of PCC exhibiting little fibrosis may show early enhancement on dynamic studies

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Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Peripheral (Intrahepatic) Cholangiocarcinoma

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