Table 1. Comparison of clinical staging systems for external auditory canal cholesteatoma (EACC)

Stage	Holt Classification (1992)28)	Naim Classification (2005)21)	Shin Classification (2010)4)	He Classification (2019)29)
I	Superficial, localized shallow concave defect or local pit in bony portion of EAC	Hyperplasia and hyperemia of the EAC epithelium	Lesion limited to the EAC	Invasion without bony lesions confined to EAC only
II	Localized deep EAC pocket formation	Local inflammation and periostitis (without bone destruction)	Invasion of tympanic membrane and middle ear (EAC+middle ear)	Confined within EAC with bone erosion or localized bone defect
III	Extension into the mastoid	EAC bone destruction with sequestrum	Invasion of mastoid air cells (EAC+mastoid)	Invasion beyond EAC but confined within temporal bone:• IIIA: Middle ear cavity invasion• IIIB: Mastoid air cell invasion• IIIC: Both middle ear cavity and mastoid invasion
IV	-	Spontaneous destruction of adjacent anatomical structures	Extension beyond temporal bone	Invasion beyond temporal bone

EAC: external auditory canal.