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Bile duct cancer, or cholangiocarcinoma, is a malignant tumour of either the bile ducts within the liver (intrahepatic), or those leading from the liver to the small intestine (extrahepatic). It is a rare tumour with poor outcome for most patients.
Microscopic deposits of tumor cells in regional lymph nodes can be detected using immunohistochemical techniques in patients without conventional histopathological evidence of lymph-node involvement. In the case of bile duct cancer, these micrometastases have an intermediate prognostic significance between that of positive and negative conventional pathology.
A new staging system for perihilar cholangiocarcinoma has recently been proposed to standardize the reporting of this intractable disease. However, the system has several flaws; thus, many revisions are needed before a registry can be established that uses this system.