Mucosal and squamosal classification of chronic otitis media
THE CONTEXT
Chronic otitis media can be described by the tissue involved and whether the disease is active, inactive or healed.
Mucosal disease
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Tubotympanic disease is mucosal disease without evidence of squamous epithelial invasion.
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Active mucosal disease has a pars tensa perforation, inflamed mucosa and mucopurulent discharge.
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Inactive mucosal disease has a permanent pars tensa perforation, uninflamed middle ear mucosa and no discharge.
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A permanent perforation means that the external squamous epithelium and internal mucosal lining of the pars tensa have fused across the perforation edge.
Healed chronic otitis media
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The tympanic membrane has healed, usually with two layers, but is atrophic and easily retracts under negative middle ear pressure.
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Tympanosclerosis may affect the tympanic membrane or middle ear, including the promontory, ossicles and tendons of stapedius and tensor tympani.
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Fibrotic tissue may be present in the middle ear. Healed chronic otitis media is always associated with some conductive hearing loss.
Squamosal disease
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Atticoantral disease is termed squamosal disease.
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Inactive squamosal disease has retraction pockets in the pars tensa, usually posterosuperiorly, or in the pars flaccida, without discharge.
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Squamous debris in a retraction pocket may become infected and begin discharging; some pockets are shallow and self-cleansing.
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Active squamosal disease implies the presence of cholesteatoma.
Significance of perforation location
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Attic and posterosuperior marginal perforations occur in dangerous CSOM and are often associated with cholesteatoma.
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Squamous epithelium from the external auditory canal can immigrate through any marginal perforation into the middle ear and form cholesteatoma, so all marginal perforations are considered dangerous.
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Central perforations are considered safe because cholesteatomas are usually not associated with them.