Iannetti classification of orbital invasion

Last revised by Francis Deng on 2 Aug 2021

The Iannetti classification grades orbital invasion by ethmoido-orbital tumors, such as adenocarcinoma, squamous cell carcinoma, adenoid cystic carcinoma, undifferentiated carcinoma, sarcoma, or olfactory neuroblastoma.


  • grade I: erosion or destruction of the orbital medial wall
  • grade II: extraconal invasion of the periorbital fat tissue
  • grade III: invasion of the medial rectus muscle, optic nerve, ocular bulb, or skin overlying the eyelid

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