Histology

• high grade (rare)
  • looks like adenosquamous carcinoma
  • cytologic atypia
  • other features
    • exophytic endobronchial growth
    • lacks in situ component
    • absence of keratinization
    • transitional areas to low grade mucoepidermoid carcinoma
• low grade
  • cystic predominance
  • mucin
  • columnar epithelium (glands, cysts)
  • squamoid cells