EPIDERMOID CHOLESTEATOMA
INTRODUCTION 4
| Description |
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In the immigration mechanism, the cholesteatoma is produced by the direct spread or immigration of the stratified squamous keratinizing epithelium from the deep external auditory meatus or the surface of the tympanic membrane into the middle ear cavity.
This direct immigration may occur in two different ways:
by the direct extension through a marginal perforation in the pars tensa or through a perforation in the pars flaccida of the tympanic membrane (a secondary acquired cholesteatoma);
or by the proliferation of the basal cells of the canal skin adjacent to the posterosuperior margin of an annulus. |
