Table 3.

Risk factors for hilar cholangiocarcinoma

Established	Less established	Potential (inconclusive data)
PSC	IBD likely via PSC	Obesity
Choledochal cysts	Cirrhosis	Tobacco smoking
Parasitic infections	Hepatitis B and C viruses	Genetic polymorphisms
Hepatolithiasis	Diabetes
Choledocholithiasis	Heavy alcohol use
Toxins (Thorotrast contrast agent)	IgG4 related cholangitis
	Abnormal junction between the common bile duct and pancreatic duct
	Helicobacter bilis
	Chronic typhoid infection

IBD: Inflammatory bowel disease; PSC: Primary sclerosing cholangitis.