Clinical approach to indeterminate biliary strictures: Clinical presentation, diagnosis, and workup

Table 1 Etiologies of biliary strictures

Benign	Malignant
Postoperative or iatrogenic strictures: After cholecystectomy, liver transplantation or surgical procedures involving pancreas. Local cancer treatment including radiation therapy, chemoembolization, and microwave ablation	Pancreatic adenocarcinoma
Chronic pancreatitis	Cholangiocarcinoma
Primary sclerosing cholangitis	Gallbladder malignancy
Trauma	Hepatocellular carcinoma
Infection: Recurrent pyogenic cholangitis, AIDS cholangiopathy	Ampullary carcinoma
Autoimmune: IgG4 related sclerosing cholangitis, sarcoidosis	Metastatic tumors or perihilar malignant nodes (colon cancer, breast cancer, renal cell cancer, squamous cell carcinoma)
Vascular: Ischemia, portal hypertensive biliopathy	Less common: Lymphomas or neuroendocrine tumors
Primary biliary cirrhosis
Rarely COVID-19 cholangiopathy, gallstones, inflammatory bowel disease or medications

IgG4: Immunoglobulin G4; AIDS: Acquired immunodeficiency syndrome; COVID-19: Coronavirus disease 2019.