Understanding cholangiocarcinoma: molecular landscape, pathological classification, and challenges in biopsy diagnosis - PubMed
5 hours ago
- #cholangiocarcinoma
- #biopsy diagnosis
- #molecular classification
- Molecular characterization of cholangiocarcinoma (CCA) challenges traditional anatomy-based classification, promoting biology-based schemes.
- Intrahepatic CCA is subdivided into small-duct and large-duct types, with large-duct type resembling perihilar CCA histologically and molecularly.
- Perihilar and distal CCAs show distinct molecular abnormalities; for example, MDM2 amplification is present in 15% of perihilar cases but absent in distal CCAs.
- Key drug targets include FGFR2 and IDH1 in small-duct intrahepatic CCA, and HER2 in extrahepatic CCA and gallbladder cancer, with HER2 overexpression in 17%-30% of cases.
- Mismatch repair (MMR) deficiency is most common in small-duct intrahepatic CCA.
- Biopsy diagnosis of intrahepatic CCA can be challenging, but awareness of pitfalls like hybrid morphology and use of ancillary markers (e.g., CRP, albumin-ISH, S100P) aids accurate classification.
- Distinguishing distal CCA from pancreatic head cancer is crucial for treatment strategies; features like clear or foamy cancer cells in biopsies may favor pancreatic ductal carcinoma over distal CCA.