Otology seminar
R3 李建林 96.03.28
External ear canal cholesteatoma and keratosis obturans
1. 1850 Toynbee first used the term molluscum contagiosum described a pearly
white shining mass occupying the posterior surface of external canal.
2. 1874 Werden described an epithelial plug occluding the external ear canal.
3. By the late 19th century the term cholesteatoma of the external auditory canal
began appearing in the English literature ( 1893 Schofield introduced the term)
4. 1980 Piepergerdes et al reviewed the literature and highlighted the differences
between the two disorders.
Cholesteatoma of external ear canal:
一. Incidence:
Anthony and Anthony report in 1982: an incidence of 1.2 primary cases per 1000 new
otological patients
Vrabec and Chaljub report in 2002: 1.7 primary cases per 1000 patients; the incidence
of all cases was 5 cases per 1000 patients
Owen and Rosborg report in 2006: 3.7 primary cases per 1000 patients; the incidence
of all cases was 7.1 cases per 1000 patients
二. Definition:
Cholesteatoma of external ear canal is the invasion of squamous tissue into a
localized area of bony erosion of the ear canal
三. Classification:
Tos report in 1997 and classified cholesteatoma of external ear canal as
1. primary cholesteatoma of external ear canal
2. secondary cholesteatoma of external ear canal
3. cholesteatoma associated with congenital atresia of the ear canal
Vrabec and Chaljub report in 2000 classified cholesteatoma of external ear canal as
1. Spontaneous cholesteatoma of external ear canal: no history of previous ear
disease, significant trauma, or surgery.
2. Congenital cholesteatoma of external ear canal: congenital stenosis of EEC
3. Iatrogenic cholesteatoma of external ear canal: previous middle ear surgery
4. Post-traumatic cholesteatoma of external ear canal: history of temporal bone
fracture or EEC fracture
5. Post-obstructive cholesteatoma of external ear canal: secondary to a lesion
occluding the EEC
6. Post-inflammatory cholesteatoma of external ear canal: history of infectious ear
disease
四. Distributions of age, gender and side:
Owen et al. (2006):
random risk of gender and random occurrence of side
五. Symptoms:
Owen et al. (2006):
otalgia (chronic dull pain) and otorreha are the most common symptoms
六. Location and extension of the cholesteatoma of external ear canal
 even distribution of location between the anterior, inferior and posterior walls
七. Pathophysiology:
Two main theories proposed ( Persaud et al. 2004 review)
1. EEC skin minor trauma  local inflammation and ulceration  local periosteitis
and osteonecrosis  proliferation and invasion of the affected bone by squamous
epothelium  formation of cholesteatoma
2. Aging skin epithelium poor blood supply  hypoxia  decreased migratory rate
 trapping desquamated epithelial cells  formation of cholesteatoma
八. Staging:
Naim et al. in 2005:
Pre-operative HRCT of temporal bone:
Stage I: local treatment with salicylate and cortisone
Stage II-VI: surgical removal
九. Treatment:
1. The exact operation is determined by the extent of the osteonecrosis,
erosion and the surgeon’s own judgement.
2. postauricular incision and then transcanal approach for adequate
debridement
skin defect (+): obliteration with an subcutis-muscle periosteum flap
skin defect (-): normal skin replace with fascia underlay
Keratosis Obturans
一. Definition:
Accumulation of obstructing plugs of desquamated keratin in the external ear
canal
二. Distributions of age, gender and side
Morrison report 50 cases in 1956: 70 % patients with keratosis obturans
were under 20 years of age and 44% were bilateral
Black and Clayton report wax keratosis in children in 1958: 90 %
incidence of bilaterally
三. Symptoms
Morrison: 80 % patients with acute and severe otalgia and then conductive
hearing loss. Besides, 77% of children with keratosis obturans had either
bronchiectasis or sinusitis but only 20% of patients over 20 years with
either disorder
四. Location and extension of the keratosis obturans
1. A large desquamating keratin plug occluding the external ear canal.
2. Upon removal of the epidermal plug, the external bony canal is noted
to be widened circumferentially due to bony re-absorption
(ballooning of external ear canal) The tympanic membrane maybe
normal but usually is thickened from the pressure of the keartin plug
五. Etiological factors: still unclear but maybe a persisting sequel of eczema,
seborrhea or frurnculosis.
六. Pathophysiology
Morrison report in 1956: broncheotracheosinusitis  sympathetic nervous
system reflex stimulate the cerumen glands  hyperemia and erythema of
the canal skin and possible areas of granulation  keratin plugs develop
Paparella and Shumrick: overproduction of epithelial cells, faulty
migration and inability of the canal to clean itself.
七. Treatment:
Require regular life-long micro-suctioning of keratinous debris because of
the failure of the normal migratory mechanism.
The frequency of cleaning varies and is indicted often by hearing loss or the
keratin re-accumulate.
Comparison of Cholesteatoma of external ear canal and keratosis obturans
Reference:
1. Piepergerdes MC, Kramer BM, Behnke EE: Keratosis obturans and external
auditory canal cholesteatoma. Laryngoscope 1980,90:383-391.
2. Naiberg J, Berger G, Hawke M: The pathologic features of keratosis
obturans and cholesteatoma of the external auditory canal. Arch Otolaryngol
1984, 110:690-693.
3. Owen HH, Rosborg J, Gaihede M: Cholesteatoma of the esternal canal:
etiological factors, symptoms and clinical findings in a series of 48 cases.
BMC Ear, Nose and Throat Disorder 2006, 6:16
4. Persaud RA, Hajioff D, Thevasagayam MS, Wareing MJ, Wright A:
Keratosis obturans and external ear canal cholesteatoma: how and why we
should distinguish between these conditions. Clin Otolaryngol Allied Sci 2004,
29:577-581.
5. Tos M: Cholesteatoma of the external acoustic canal. In Manual of middle ear
surgery vol. 3: Surgery of the external auditory Thieme;1997:205-209.
6. Naim R, Linthicum F Jr., Shen T, Bran G, Hormann K: Classification of the
external auditory canal cholesteatoma. Laryngoscope2005, 115:455-460.
7. Vrabec JT, Chaljub G: External canal cholesteatoma. Otol Neurotol 2002,
23:241-242.
8. Anthony PF, Anthony WP: Surgical treatment of external auditory canal
cholesteatoma. Laryngoscope 1982, 92:70-75.