Table 1.

Classification Systems for Staging Extent of Airway Involvement

Stage	Czaja and McCaffrey (14)	Shin et al. (18)
I	Extra thyroid extension adherent to airway with no gross invasion	Invasion of perichondrium
II	Gross invasion which can be excised without mucosal disruption	Invasion of the cartilage
III	Gross invasion which requires mucosal disruption to excise but no intraluminal invasion	Involvement of submucosa
IV	Gross intraluminal invasion	Intraluminal invasion