Table 1 Naim et al. classification of EACC [17]

Stage I

Epithelial hyperplasia

Stage II

Hyperplastic epithelial inflammation with surrounding periostitis. Superimposed infection causes purulent otorrhoea

Subclass IIA

Intact epithelium

Subclass IIB

Epithelial defect with osseous denudation

Stage III

Necrobiotic excavation of the osseous EAC which accumulates keratin

Stage IV

Extension into adjacent anatomical structures

Subclass IVM

Mastoid

Subclass IVS

Skull base with involvement of the sigmoid sinus

Subclass IVJ

Temporomandibular joint

Subclass IVF

Facial nerve