2. Definition
ā¢ The term coined by Johannes Muller in 1838.
ā¢ defined as a cystic structure filled with desquamated
squamous debris lying on fibrous matrix.(skin in wrong
place)
Currently the Definition is,
ļ A three dimensional epidermoid structure
ļ Exhibiting independent growth
ļ Replacing the middle ear mucosa and resorption of the
underlying bone.
3. Histologically
ā¢ Cystic Content
o is composed of fully differentiated anucleate keratin squames.
ā¢ Matrix
o contains keratinizing squamous epithelium lining a cyst like
structure.
ā¢ Perimatrix
o known as lamina propria
o peripheral part of cholesteatoma consists of granulation tissue
and cholesterol granules.
o This layer is in contact with the bone. It is the granulation tissue
which releases enzymes that cause bone destruction.
5. Classification
Can be classified as,
ā¢ Congenital cholesteatoma
ā¢ Acquired cholesteatoma.
o Primary acquired cholesteatoma
o Secondary acquired cholesteatoma
6. Primary acquired
ā¢ Etiology unknown
ā¢ there is no history of preexisting or previous episodes of
otitis media or perforation. Lesions just arise from the
attic region of the middle ear.
ā¢ Various theories have been proposed to explain the
pathophysiology
7. Pathophysiology
Cawthrone theory:
ā¢ suggested by Cawthrone in 1963
ā¢ that cholesteatoma always originated from
congenital embryonic cell rests present in
various areas of the temporal bone.
8. Pathophysiology
Tumarkinās theory:
ā¢ cholesteatoma is derived by immigration of
squamous epithelium from the deep portion of
the external auditory canal into the middle ear
cleft through a marginal perforation or a total
perforation.
9. Pathophysiology
Toss theory of invagination:
ā¢ persistent negative pressure in the attic region
causes invagination of pars flaccida causing a
retraction pocket.
ā¢ This retraction pocket becomes later filled with
desquamated epithelial debris which forms a
nidus for the infection to occur later.
ā¢ Common organisms to infect this keratin debris
are Psuedomonas, E. coli, Proteus etc.
10. Retraction pockets
ā¢ A retraction pocket is an invagination of the
tympanic membrane. The negative middle ear
pressure, which is the cause of retraction pocket
ā¢ Toss classified attic retraction pockets into 4
grades:
11. ā¢ Grade I: The pars flaccida is not in contact with the neck
of the malleus.
ā¢ Grade II: The retracted pars flaccida is in contact with
the neck of the malleus and clothing it.
ā¢ Grade III: Here in addition to grade II features there is
minimal erosion of the outer attic wall
ā¢ Grade IV: In this grade in addition to all the above said
changes there is severe erosion of the outer attic wall
or scutum.
12. Pathophysiology
Metaplasia:
ā¢ This theory was first suggested by Wendt in
1873.
ā¢ The epithelium in the attic area of the middle
ear undergoes metaplastic changes in response
to subclinical infection.
ā¢ This metaplastic mucosa is squamous in nature
there by forming a nidus for cholesteatoma
formation in the attic region.
14. Secondary acquired
ā¢ This always follows active middle ear infection which
destroy the tympanic membrane along with the annulus.
ā¢ The destruction of annulus predisposes to epithelial
migration from the external auditory canal into the attic
region
15. Pathology
ā¢ Necrosis of tympanic membrane tissue along with its
annulus. caused due to the virulence of the organisms
involved i.e. beta-hemolytic streptococci.
ā¢ Necrosis starts to occur in those areas of ear drum
which have the poorest blood supply.
16. Congenital Cholesteatoma
ā¢ Are epidermoid tumors originating from the
embryonic epidermoid rest located in the
temporal bone or adjacent meningeal spaces.
ā¢ It appears as whitish globular masses lying
medial to an intact tympanic membrane.
17.
18.
19. Pathogenesis
Teedās epithelial cell rest theory:
ā¢ Suggested by Teed in 1936
ā¢ the persistence of squamous epithelial cell rests
in the temporal bone lead to the formation of
congenital cholesteatoma.
20. Pathogenesis
Implantation theory:
ā¢ Friedberg suggested, viable squamous epithelial
cells in the amniotic fluid present in the middle
ears of neonates and hypothesized that this was
a possible source of congenital cholesteatoma
21. Pathogenesis
Ruedi's invagination theory:
ā¢ This theory suggests that in utero infection of
tympanic membrane causes invagination of ear
drum into the middle ear cavity causing
congenital cholesteatoma.
23. Causes of bone destruction
ā¢ Hyperaemic decalcification
ā¢ Osteoclastic bone resorption due to:
o Acid phosphatase
o Collagenase
o Acid proteases
o Proteolytic enzymes
o Leukotrienes
o Cytokines
ā¢ Pressure necrosis: No role
ā¢ Bacterial toxins: No role
24. Evaluation
ā¢ History
ā¢ Head and neck examination
ā¢ Otologic examination
ā¢ tuning fork examination-conductive hearing loss
ā¢ Hearing evaluation (PTA) -conductive hearing loss
ā¢ Tympanometry-Flat tympanograms
ā¢ CT scan of temporal bones
25. Complications
ā¢ Infection
ā¢ Otorrhea
ā¢ Bone destruction
o Ossicles, tegmen
ā¢ Hearing loss
ā¢ Facial nerve paresis or paralysis
ā¢ Labyrinthine fistula
ā¢ Intracranial complications
26. Management
ā¢ Aural toilet
ā¢ Antibiotics
ā¢ Grommet insertion (to manage early retraction pockets)
ā¢ Canal wall down mastoidectomy
27. Aural toilet
ā¢ Done only for active stage
ā Dry mopping with cotton swab
ā Suction clearance: best method
ā Gentle irrigation (wet
mopping) Removes
accumulated debris
Acidic pH discourages bacterial growth