Epithelial

• adenoma
  • tubular adenoma
  • villous adenoma
  • tubulovillous adenoma
• dysplasia
  • low grade dysplasia
  • high grade dysplasia
• hamartoma
  • juvenile polyp
  • Peutz Jeghers polyp
• carcinoma
  • adenocarcinoma
    • mucinous adenocarcinoma
    • signet ring carcinoma
  • adenosquamous carcinoma
  • medullary carcinoma
  • SCC
  • undifferentiated carcinoma
• neuroendocrine neoplasm
  • gangliocytic paraganglioma
  • glucagon-like peptide producing neuroendocrine carcinoma

Mesenchymal

• leiomyoma
• lipoma
• angiosarcoma
• GIST
• Kaposi sarcoma
• Leiomyosarcoma

Hematolymphoid

Metastasis

Ampullary tumors

• contains a mixture of small intestine and biliary tumors
• see gallbladder section for biliary tumors