Cholesteatoma
Cholesteatoma is a self-renewing collection of keratinising squamous epithelium in the middle-ear cleft or mastoid that can erode bone, damage hearing and spread infection; it is not a tumour and needs specialist ENT assessment.
Definition
Cholesteatoma is an expansile collection of keratinising squamous epithelium in the middle-ear cleft or mastoid. It may be congenital behind an intact tympanic membrane or acquired, most often from a retraction pocket, and can erode surrounding bone.
First principles
Trapped skin keeps producing keratin
A cholesteatoma contains keratinising squamous epithelium in a location where skin cannot migrate out and clear. Keratin accumulates in an expanding sac, so the lesion persists even when discharge temporarily improves.
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