Most common type of CCA
Well circumscribed, large, with lobulated margins
Multicentricity, especially around main tumor
•
Periductal-infiltrating CCA
Grows along bile ducts and is elongated, spiculated, or branch-like
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Progressive, gradual, and concentric filling (centripetal) on delayed phase images
Usually not isodense to vessels (unlike hemangioma)
•
Substantial
delayed enhancement (i.e., greater than that of liver parenchyma) is common (74%)
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
Duct lining may be thickened and enhanced
Rare with other types of hepatic tumors
TOP DIFFERENTIAL DIAGNOSES
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Hepatic metastases and lymphoma
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Hepatocellular carcinoma
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Focal confluent fibrosis
PATHOLOGY
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Based on growth characteristics
Mass forming (exophytic/nodular); most common form
Periductal infiltrating (sclerosing)
Intraductal growing (polypoid/papillary)
CLINICAL ISSUES
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Only minority of cholangiocarcinomas are peripheral type
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Large size at presentation contributes to poor prognosis
TERMINOLOGY
Abbreviations
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Cholangiocarcinoma (CCA)
Synonyms
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Cholangiocellular carcinoma, intrahepatic cholangiocarcinoma
Definitions
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CCA: Adenocarcinoma arising from bile duct epithelium (cholangiocytes)
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Peripheral CCA: Tumor arising from intrahepatic bile ducts
IMAGING
General Features
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Best diagnostic clue
Infiltrative hepatic mass with capsular retraction and delayed persistent enhancement (CECT and MR)
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Location
Originates from interlobular bile ducts (i.e., bile ducts distal to 2nd order branches)
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Size
Usually large (> 5 cm) at diagnosis
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Morphology
Peripheral CCA is usually a mass-forming tumor
–
Often has “satellite” nodules
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Key concepts
Mass-forming CCA: Well circumscribed, large, with lobulated margins
–
Multicentricity, especially around main tumor
Periductal-infiltrating CCA: Grows along bile ducts and is elongated, spiculated, or branch-like
Intraductal-growing CCA: Small, sessile, or polypoid
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Often spreading superficially along mucosal surface and resulting in multiple tumors (papillomatosis) along various segments of bile ducts
CT Findings
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NECT
Well-defined, predominantly homogeneous, hypodense mass
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Hypodense satellite nodules (65% of CCAs)
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Punctate, stippled, chunky calcifications (18% of CCAs)
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CECT
Mass-forming PCC
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Thin or thick rim-like enhancement frequently seen around periphery of tumor on arterial phase images
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Progressive, gradual, and concentric filling (centripetal) on delayed phase images
Usually not isodense to vessels (unlike hemangioma)
–
Substantial
delayed enhancement (i.e., > that of liver parenchyma) is common (74%)
Attributed to fibrous stroma in CCA
–
Homogeneous or heterogeneous hyperattenuating enhancement
Entire mass may be enhanced only on delayed-phase images
May be only evidence of tumor
–
±
capsular retraction (frequent), with parenchymal atrophy of liver segments peripheral to tumor
Bile ducts will be dilated upstream from tumor
–
May not be evident in very peripheral CCA
–
Duct lining may be thickened and enhanced
Rare for hepatic metastases or other hepatic primary tumors
MR Findings
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T1WI
Heterogeneous hypointense mass
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T2WI
Hyperintense periphery (cellular tumor) + large central hypointensity (fibrosis)
Hyperintense foci in center may represent necrosis, mucin
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T1WI C+
Central hypointense areas exhibit homogeneous, heterogeneous, or no enhancement
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Regions of fibrosis display enhancement (delayed) while those of coagulative necrosis and mucin show no enhancement
Dynamic MR: Minimal or moderate rim enhancement and progressive and concentric filling with contrast material
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Intratumoral fibrous stroma displays marked or prolonged enhancement on delayed phase scans
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Diagnostic Imaging_ Gastrointes - Michael P Federle