Gastrointestinal and Hepatobiliary · Biliary tract · Original 1975 classification with commonly used modern terminology
Bismuth–Corlette Classification of Perihilar Cholangiocarcinoma
An anatomical classification of perihilar cholangiocarcinoma based on the longitudinal extent of tumour involvement within the hepatic duct confluence and right or left hepatic ducts.
Purpose
To describe the longitudinal biliary extent of a perihilar cholangiocarcinoma and support communication, operative planning and selection of ducts or liver segments for drainage.
| Type | Biliary involvement | Key interpretation |
|---|---|---|
| I | Common hepatic duct below the right–left hepatic duct confluence | Confluence is not involved |
| II | Tumour reaches and involves the hepatic duct confluence without extension into either main hepatic duct | Confluence involved; no unilateral ductal extension |
| IIIa | Confluence involvement with extension into the right hepatic duct | Right-sided ductal extension |
| IIIb | Confluence involvement with extension into the left hepatic duct | Left-sided ductal extension |
| IV | Extension into both right and left hepatic ducts or multifocal biliary involvement | Bilateral or multifocal ductal disease |
How to use it
- The classification describes longitudinal spread along the biliary tree; it is not a complete staging system.
- Contrast-enhanced MRI with MRCP is useful for mapping biliary involvement and should ideally be performed before biliary intervention.
- Type III is unilateral: IIIa denotes right-sided extension and IIIb denotes left-sided extension.
- Resectability also depends on vascular involvement, lobar atrophy, future liver remnant, nodal disease and distant metastases, none of which is adequately captured by this classification.
Common mistake
Do not reverse type IIIa and IIIb: IIIa is right and IIIb is left. A type IV tumour should not be declared unresectable solely from the Bismuth–Corlette category; comprehensive vascular, hepatic and metastatic assessment is required.
Exam pearl
Read the classification from the confluence upwards: below the confluence is type I, at the confluence is type II, one side is type III, and both sides or multifocal disease is type IV.
Viva questions
- What is the Bismuth–Corlette classification?
- It is an anatomical classification of perihilar cholangiocarcinoma based on the longitudinal extent of tumour involvement in relation to the hepatic duct confluence and the right and left hepatic ducts.
- Enumerate the Bismuth–Corlette types.
- Type I is below the confluence, type II involves the confluence, type III extends unilaterally into either hepatic duct, and type IV shows bilateral or multifocal biliary involvement.
- How do types I and II differ?
- Type I remains below the right–left hepatic duct confluence, whereas type II reaches and involves the confluence without extending into either main hepatic duct.
- How do types IIIa and IIIb differ?
- Type IIIa extends into the right hepatic duct, whereas type IIIb extends into the left hepatic duct.
- What constitutes a Bismuth–Corlette type IV tumour?
- Type IV denotes extension into both right and left hepatic ducts or multifocal biliary involvement.
- What is the clinical importance of the Bismuth–Corlette classification?
- It communicates the longitudinal biliary extent of perihilar cholangiocarcinoma and assists planning of resection and biliary drainage. It must be combined with assessment of vascular, hepatic, nodal and metastatic disease.
- What are the major limitations of the Bismuth–Corlette classification?
- It does not adequately describe vascular invasion, lobar atrophy, future liver remnant, lymph-node involvement or distant metastases. Therefore, it cannot independently determine stage, prognosis or resectability.