biliary tract


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  • Normal

    • gallbladder
      • mucosa
        • simple columnar epithelium
          • basal or central nuclei
          • pink cytoplasm
          • scattered basal cells (mimicks lymphocytes)
          • scattered penciloid cells
          • small apical vacuoles
        • lamina propria
      • Gallbladder lacks muscularis mucosa and submucosa
      • muscularis
      • perimuscular connective tissue
        • mucous glands
        • accessory bile duct
      • serosa or adventitia (liver bed)
    • cystic duct
      • same as gallbladder
      • mucous glands in lamina propria
    • bile duct
      • epithelium
        • simple columnar epithelium
        • basal nuclei
      • subepithelial stroma
        • epithelial invaginations (sacculi of Beale)
      • peribiliary connective tissue
        • mucous glands
          • aka: peribiliary glands
          • cuboidal-low columnar
          • prominent mucin
          • nice lobular architecture (vs carcinoma)
        • nerves
        • vessels
    • ampulla
      • ampullary epithelium
        • simple columnar
        • scattered goblet cells
      • accessory pancreatic ducts and acini
      • pancreatic duct
      • common bile duct
      • sphincter of Oddi
    • biliary tree
      • left + right hepatic duct
      • common hepatic duct
      • merges with cystic duct from gallbladder
      • common bile duct
      • merges with pancreatic duct
      • ampulla
  • Non-neoplastic

  • WHO neoplasms

    • Bile duct adenoma
    • BilIN
    • papillary neoplasm
    • mucinous cystic neoplasm
    • adenocarcinoma
      • biliary type adenocarcinoma
      • foveolar type adenocarcinoma
      • intestinal type adenocarcinoma
      • clear cell adenocarcinoma
      • mucinous adenocarcinoma
      • signet ring carcinoma
    • adenosquamous carcinoma
    • SCC
    • undifferentiated carcinoma
    • carcinosasrcoma
    • cribiform carcinoma
    • neuroendocrine
      • carcinoid
      • atypical carcinoid
      • small cell carcinoma
      • large cell neuroendocrine carcinoma
      • mixed adenoneuroendocrine carcinoma
      • goblet cell carcinoid
      • tubular carcinoid
    • mesenchymal
      • granular cell tumor
      • leiomyoma
      • Kaposi sarcoma
      • leiomyosarcoma
      • rhabdomyosarcoma
    • lymphoma
    • metastasis
    • ampullary tumor
      • contains a mixture of small intestine and biliary tumors
      • see small intestine section for small intestine tumors
  • See liver for intrahepatic ddx

  • TNM (useful for grossing)

    • Gallbladder
      • Tis: in situ
      • T1a: lamina propria invasion
      • T1b: muscularis invasion
      • T2: confined within serosa or adventitia
      • T3: serosa perforation, liver invasion, extrahepatic bile duct invasion, or adjacent structure invasion
      • T4: portal vein, hepatic artery, or multiple extrahepatic structure invasion
      • Regional nodes include cystic duct, common bile duct, hepatic artery, portal vein
    • Distal bile duct
      • Tis: in situ
      • T1: bile duct confined
      • T2: through bile duct wall
      • T3: gallbladder, liver, pancreas, duodenum, or other organ invasion
      • T4: celiac axis or SMA involvement
    • Perihilar bile duct
      • Tis: in situ
      • T1: bile duct confined
      • T2a: fat invasion
      • T2b: liver invasion
      • T3: unilateral branch invasion of portal vein or hepatic artery
      • T4: main stem or bilateral branch invasion (portal vein, common hepatic artery). Or, 2nd order biliary radicals either bilaterally or with contralateral vessel (portal vein or hepatic artery) involvement.
  • Staging

    • Gallbladder and distal bile duct
      • 0: Tis
      • I: T1
      • II: T2
      • IIIA: T3
      • IIIB: N1
      • IVA: T4
      • IVB: M1
    • Perihilar bile duct
      • 0: Tis
      • I: T1
      • II: T2a,b
      • IIIA: T3
      • IIIB: N1
      • IVA: T4
      • IVB: M1