Cholangiocarcinoma

Brooke R. Jeffrey, MD

Amir A. Borhani, MD

Key Facts

Imaging

Klatskin tumor: Small hilar mass obstructing bile ducts on CT or ERCP
Cholangiography (PTC/ERCP)
- Important to determine extent of intra- and extrahepatic duct involvement
- Extension up right or left duct often precludes surgical resection
CECT
- Portal phase: Minimal enhancement of irregularly thickened bile duct wall and distal ductal dilatation
- Delayed phase: Persistent enhancing tumor (due to fibrous stroma)
MR
- Superior to CT for detection of small hilar tumors, intrahepatic & periductal tumor infiltration
- Shows location of obstruction and IHBD dilatation

Top Differential Diagnoses

Pancreatic ductal carcinoma
Chronic pancreatitis
Choledocholithiasis
Primary sclerosing cholangitis
Autoimmune pancreatitis/cholangitis
Inflammatory hepatic pseudotumor

Pathology

Tumor types
- Exophytic intrahepatic masses (nodular type)
- Scirrhous infiltrating neoplasms (sclerosing type): Cause strictures
- Polypoid neoplasms of ductal wall (papillary type): Bulge into bile duct lumen
Risk factors
- PSC
- Fibropolycystic liver disease (choledochal cysts)

(Left) Drawing of an axial section through the liver shows a Klatskin tumor

, a small mass at the confluence of the main right and left bile ducts invading the adjacent liver and the hepatic vein. The intrahepatic ducts are dilated, and the liver is bile stained. (Right) Cholangiogram shows a mass

at the confluence of the main right and left ducts with marked dilatation of the intrahepatic bile duct. The common hepatic duct is involved, but the cystic and common bile ducts are not.

(Left) Axial CECT shows intrahepatic bile duct dilation

ending abruptly at a small mass

near the hepatic hilum. The lateral segment atrophy

is a secondary sign of longstanding obstruction. (Right) Axial CECT in the same patient on a 10 minute delayed scan shows delayed retention of contrast in the tumor

, reflecting the fibrous stroma component that is typical of cholangiocarcinomas. This is a classic example of a Klatskin tumor with direct hepatic invasion.

TERMINOLOGY

Abbreviations

Cholangiocarcinoma (CCa)

Synonyms

Cholangiocellular or bile duct adenocarcinoma

Definitions

Malignancy arising from intrahepatic bile duct (IHBD) or extrahepatic bile duct epithelium

IMAGING

General Features

Best diagnostic clue
- Klatskin tumor: Small hilar mass obstructing bile ducts on CT or ERCP
Location
- Distribution in different segments of biliary tree
  - Distal common bile duct (CBD) (30-50%)
  - Common hepatic duct (14-37%)
  - Proximal CBD (15-30%)
  - Confluence of hepatic ducts (Klatskin tumor) (10-26%)
  - Isolated left or right hepatic duct (8-13%)
  - Cystic duct (6%)
- Classified based on anatomy and radiography
  - Peripheral (10%)
    - Intrahepatic; proximal to secondary biliary radicles
  - Perihilar (50%)
    - Klatskin tumor: Hilar tumor involving the confluence of hepatic ducts
  - Distal (40%)
    - Extrahepatic; distal CBD
    - May arise as short stricture or small polypoid mass
Size
- Peripheral cholangiocarcinoma (5-20 cm)
- Perihilar and extrahepatic types much smaller
Morphology
- Infiltrative (sclerosing)
- Exophytic (nodular)
- Papillary

Radiographic Findings

Cholangiography (PTC/ERCP)
- Papillary intraductal tumor mass (2-5 mm in diameter)
- Infiltrating type: Frequently long, rarely short, concentric focal stricture
- Ductal wall irregularities, prestenotic diffuse/focal biliary dilatation
- Hilar strictures (due to Klatskin tumor): Proximal bile duct dilatation
- Important to determine extent of intra- and extrahepatic duct involvement
  - Extension up right or left duct often precludes surgical resection

CT Findings

NECT
- Intrahepatic
  - Peripheral hypodense solitary or satellite lesions and IHBD dilatation
    - Capsular retraction is often seen
  - Central (hilar) hypodense mass at confluence and IHBD dilatation
- Extrahepatic: Common duct
  - Small mass (hard to detect on CT or MR)
  - Large growth (seen as hypodense mass) and IHBD dilatation
CECT
- Arterial phase
  - Early rim enhancement with progressive, central, patchy enhancement
- Portal phase
  - Minimal enhancement of irregularly thickened bile duct wall
    - Dilated IHBD
  - Invasion of portal vein often seen with intrahepatic type
  - Enlarged portal lymph nodes may be seen
- Delayed phase
  - Persistent enhancing tumor (due to fibrous stroma)

MR Findings

T1WI
- Iso- or hypointense
T1WI FS
- Shows tumor of intrapancreatic portion of CBD as low signal intensity against high signal intensity of pancreatic head
T2WI
- Hyperintense periphery (viable) and central hypointensity (fibrosis)
T1WI C+
- Superior to CT in detecting small hilar tumors, intrahepatic and periductal tumor infiltration
MRCP
- Reveals site and extension of tumor growth
- Shows location of obstruction and IHBD dilatation

Ultrasonographic Findings

Grayscale ultrasound
- Mixed echoic, homo-/heterogeneous mass and dilated IHBD
- Dilated intra- and extrahepatic bile ducts if lesion is in CBD
Endoscopic ultrasound (EUS)
- Reported higher sensitivity than CT, US, and cholangiography

Angiographic Findings

Conventional
- Avascular, hypo-/hypervascular
- Poor or absent tumor stain
- Hepatic artery and portal vein
  - Displacement, encasement, or occlusion