Keratosis obturans (KO) is a rare external auditory canal disease characterised by abnormal accumulation and consequently occlusion and expansion of the bony portion of the EAC by a plug of desquamated keratin. It can be confused by EAC cholesteatoma but they are completely different entities require different treatment approach.
KO is seen in younger patients usually less than 40 years old and is bilateral in 50% of cases.
Patients present with acute severe pain and conductive hearing loss.
Cause is not clear in majority of cases.
Keratosis obturans is characterized by:
- dense plug of keratin debris within the deep meatus
- hyperplasia of the underlying epithelium
- chronic inflammation within the subepithelial tissue
- remodeling and expansion of the canal
- no evidence of erosion or necrosis of the underlying bone
- chronic para nasal sinus disease
*particularly in pediatric group which these concurrent findings approaches 80%; but only in 20% of adult patients
Temporal bone CT scan
- well defined soft tissue mass within the bony EAC which may diffusely enlarges the canal with no bony erosion as opposed to the EAC cholesteatoma
- tympanic canal is usually spared but may be slightly thickened
Usually treated by EAC toilet; due to high incidence of recurrence it may be requiring several excisions of keratin plugs. Rarely needs surgical intervention.
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