Pathology of Cholangiocarcinomas

Area of Science:

• Oncology
• Gastroenterology
• Pathology

Background:

• Cholangiocarcinomas (CCA) are the second most common primary liver malignancy after hepatocellular carcinoma.
• Epidemiological data indicate a rising incidence of intrahepatic CCA (iCCA) with unknown causes.
• CCA are classified by location: intrahepatic (iCCA), perihilar (pCCA), and distal (dCCA).

Purpose of the Study:

• To review the classifications and subtypes of cholangiocarcinomas.
• To discuss the mode of extension, biopsy utility, and pre-neoplastic lesions in CCA.
• To provide a comprehensive overview of CCA heterogeneity.

Main Methods:

• Literature review of CCA classifications (anatomical and macroscopic).
• Description of microscopic and phenotypic subtypes of CCA.
• Analysis of CCA extension patterns and biopsy diagnostic roles.

Main Results:

• iCCA is further subdivided into small duct and large duct types, each with distinct characteristics.
• Biopsy plays a crucial role in iCCA diagnosis and differential diagnosis, particularly excluding metastases.
• Biopsies in pCCA and dCCA are more invasive, with a higher risk of false negatives due to sampling difficulties.

Conclusions:

• CCA are heterogeneous tumors requiring detailed classification and understanding of subtypes.
• Accurate diagnosis and characterization of CCA are essential for appropriate therapeutic management.
• Further research into the rising incidence and diagnostic challenges of CCA is warranted.