Expert Consensus on Pathological Diagnosis of Intrahepatic Cholangiocarcinoma (2022 version)

Abstract

Intrahepatic cholangiocarcinoma (iCCA) can originate from the large bile duct group (segment bile ducts and area bile ducts), small bile duct group (septal bile ducts and interlobular bile ducts), and terminal bile duct group (bile ductules and canals of Hering) of the intrahepatic biliary tree, which can be histopathological corresponding to large duct type iCCA, small duct type iCCA and iCCA with ductal plate malformation pattern, and cholangiolocarcinoma, respectively. The challenge in pathological diagnosis of above subtypes of iCCA falls in the distinction of cellular morphologies, tissue structures, growth patterns, invasive behaviors, immunophenotypes, molecular mutations, and surgical prognoses. For these reasons, this expert consensus provides nine recommendations as a reference for standardizing and refining the diagnosis of pathological subtypes of iCCA, mainly based on the 5 th edition of the World Health Organization Classification of Tumours of the Digestive System.

Clinicopathological features of cholangiolocarcinoma and impact of tumor heterogeneity on prognosis: A single institution retrospective study

“…CLC was pathologically defined as the proliferation of tumor cells with insufficient mucus composed of small tubular glands, antler-like or anastomotic patterns with abundant fibrous stroma by H&E staining, as previously described ( 11 , 19 ). H&E staining was performed according to our institutional protocol.…”

“…Histologically, large-duct type iCCA are characterized by cuboidal or columnar cells with mucus production constituting an irregular ductal or tubular arrangement ( 11 ). In contrast, CLC is characterized by small cuboidal cells without mucus, forming angular small ductular, antler-like or branched arrangement patterns with abundant hyalinized fibrous stroma ( 11 ). However, in clinical practice, tumors with mixed CLC and iCCA, with varying degrees of differentiation are often encountered.…”

Recent Advances in Pathology of Intrahepatic Cholangiocarcinoma

“…ICCA is highly heterogeneous in terms of cell origin, tissue structure, immunophenotype, and molecular mutations. The criteria for the histological classification of ICCA, the selection of immunohistochemical markers, the detection of molecular targets, and the differential diagnosis of histological subtypes need to be refined for better applications in practice [230].…”