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
    • mucous glands
    • epithelial invaginations
    • Rokitansky-Aschoff sinus
  • 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

• reactive
• gallbladder
  • cholelithiasis
  • cholecystitis
    • acute cholecystitis
    • chronic cholecystitis
    • xanthogranulomatous cholecystitis
    • eosinophilic cholecystitis
    • diffuse acalculous lymphoplasmacytic cholecystitis
  • Rokitansky-Aschoff sinus
  • cholesteral cleft
  • cholesterolosis
  • porcelain gallbladder
• bile duct
  • PSC
  • choledochal cyst
  • accessory bile duct
  • AJPBD
• metaplasia
  • pyloric metaplasia
  • intestinal metaplasia
• heterotopia
  • pancreas
  • adrenal
  • stomach
  • thyroid

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
• cribriform 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