Keratosis obturans

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.

Epidemiology

KO is seen in younger patients usually less than 40 years old and is bilateral in 50% of cases.

Clinical presentation

Patients present with acute severe pain and conductive hearing loss.

Pathology

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

Associations^*

• bronchiectaisis
• chronic para nasal sinus disease

_{*particularly in pediatric group which these concurrent findings approaches 80%; but only in 20% of adult patients}

Radiographic findingsfeatures

Temporal bone CT scan

• well defined soft tissue mass within the bony EAC which may diffusely enlarges the canal with nobony erosion as opposed to the EAC cholesteatoma
• tympanic canal is usually spared by may be slightly thickened

Treatment

Usually treated by EAC toilet; due to high incidence of recurrence it may be requiring several excisions of keratin plugs. Rarely needs surgical intervention.