Keratosis obturans and primary auditory canal cholesteatoma are different clinical entities involving an accumulation of keratin in the external auditory canal. Keratosis obturans involves a large plug of desquaminated keratin, while primary auditory canal cholesteatoma is characterized by an invasion of squamous tissue causing localized bony erosion. The two conditions differ in their pathology, with keratosis obturans forming a layered keratin plug and cholesteatoma forming keratin within a sac involving the bone. Treatment for keratosis obturans typically involves removing the plug, while cholesteatoma requires surgically removing the abnormal tissue and bone.

1. Keratosis obturans & primary auditory
canal cholesteatoma
Definitions: Keratosis obturans & primary auditory canal choleateatoma are different clinical &
pathological entities. In the 1980, they are defined as different entities.before that this was not
clear.
Keratosis obturans is the accumulation of a large plug of desquaminated keratin in the external
auditory meatus.
Primary auditory canal cholesteatoma is the invasion of squamous tissues from the ear into a
localized area of bony erosion.
Pathology
In keratosis obturans a geometrically patterned keratin plug within lumen of an expanded external
auditory canal is seen. The keratin are shed from the circumference of the deep ear canal forming a
lamina (onion skin arrangement).
In primary auditory canal cholesteatoma , the keratin is derived primarily from a sac that involves
the bone of the ear canal with bony fragments within it & random keratin in the lumen of the ear
canal.
Keratosis obturans Primary auditory canal
cholesteatoma
Aetiology Abnormal epithelial migration,
more than one disease.
Abnormal bone leading to
migration of epithelium into
this bone.
Symptoms/signs Severe otalgia,conductive
hearing loss, younger ages ,
occasionally bilateral,associated
with lung & sinus disease, can
present with a plugged feeling.
Chronic otorrhoea with normal
hearing, itchiness, or pain.
Older populations, usually
unilateral.
Pathology Keratin plug occluding canal ,
TM thicken& standing out in
relief in a widened ear canal.
Ear canal grossly widen or
ballooned. Can cause extensive
bony erosion including
automastoidectomy.Hyperaemia
of the ear canal with
Keratin in random pattern
TM normal
Localised osteitis/ erosion of
the canal usually
posterioinferior,
Sequestration of bone.

2. granulations.
Treatment Removal of plug
Local treatment of granulations
Biopsy to exclude
malignancy/necrotizing otitis
externa.
May need continued cleanings.
Surgically remove
cholesteatoma & abnormal
bone ,
Graft with fascia
Biopsy .
D/D Impacted wax with infection,
Neoplastic disease.
Necrotizing otitis externa,
Benign sequestrum,
Neoplastic disease.
Management options
The pain & deafness associated with keratosis obturans means that it is necessary to remove it often
under G/A. Canaloplasty has been suggested for recurrent keratosis obturans with good results.
Primary auditory canal cholesteatoma ,conservative treatment is used where the extent of the
cholesteatoma erosion can be seen. When this is not possible , patients are treated with excision of
necrotic bone &cholesteatoma via the mastoid & repair of the defect using temporal fascia.