intrahepatic cholangiocarcinoma

Definition : Intrahepatic cholangiocarcinoma (iCCA) is a malignant intrahepatic epithelial neoplasm with biliary differentiation, arising in the liver periphery / proximal to the left and right hepatic ducts (WHO 2019)

Microscopical synopsis

 iCCA consists of infiltrating well formed or cribriform glands in an abundant fibrous stroma (Liver Int 2019;39:7, Surg Pathol Clin 2018;11:403)
 Malignant glands are lined by cells with varying degrees of atypia and pleomorphism (Liver Int 2019;39:7)
 Usually well differentiated adenocarcinoma with mild atypia, intracytoplasmic lumina and intraluminal cellular debris; however, focal atypia with marked pleomorphism can also be present (Liver Int 2019;39:7)
 Commonly infiltrates between hepatic parenchymal cords at the periphery of the tumor
 Multicentricity and perineural invasion are common

Variants

Histologic variants include :
 Small duct type iCCA
 Large duct type iCCA
 mucinous,
 signet ring cell,
 clear cell,
 lymphoepithelioma-like,
 thyroid follicular-like,
 adenosquamous
 sarcomatoid