Pathological classification of intrahepatic cholangiocarcinoma based on a new concept

Table 1 High risk factors and underlining causes of intrahepatic cholangiocarcinoma

Chronic inflammatory biliary diseases

Primary sclerosing cholangitis/Ulcerative colitis

Hepatolithiasis

Liver flukes and other biliary parasite infections

Others

Biliary malformation and developmental disorders

Caroli’s disease

Congenital hepatic fibrosis

Biliary-pancreatic maljunction

Simple, solitary or multiple, hepatic cyst

Polycystic liver

Others

Chronic advanced, non-biliary, liver diseases

Chronic hepatitis/cirrhosis related to HCV and HBV infection

Non-alcoholic fatty liver disease

Others

Thorotrast deposition

EB virus infection

Others

HCV: hepatitis C virus; HBV: hepatitis B virus; EB: Epstein-Barr.

Table 2 Classification of intrahepatic cholangiocarcinoma

New classification of ICC	Traditional classification of ICC
Conventional type (bile duct type type)	Adenocarcinoma
Small bile duct type (peripheral type)	Well differentiated
Well differentiated	Moderately differentiated
Moderately differentiated	Poorly differentiated
Poorly differentiated
Large bile duct type (perihilar type)
Well differentiated
Moderately differentiated
Poorly differentiated
Bile ductular type
Intraductal type
Papillary type
Tubular type
Superficial spreading type
Rare variants	Rare variants
Squamous/adenosquamous cell type	Squamous/adenosquamous cell type
Mucinous/signet ring cell	Mucinous/signet ring cell
Clear cell type	Clear cell type
Undifferentiated type	Undifferentiated type
Lymphoepithelial type	Lymphoepithelial type
Others	Others

ICC: intrahepatic cholangiocarcinoma.