Cholesteatoma

Question 1

Classification of cholesteatomas

Answer 1

Congenital
Acquired primary
Acquired secondary

Question 2

Parts of cholesteatoma

Answer 2

Matrix (keratinizing squamous epithelium)

Keratin debris / epidermosis / keratoma

Question 3

Theories of genesis of cholesteatoma

Answer 3

Congenital cell rests

Invagination (tympanic membrane)(Wittmaack’s theory)

Ruedi’s theory (basal cell hyperplasia)(influence of infection)

Habermann’s theory (epithelial invasion)

Sade’s theory (metaplasia of middle ear mucosa)(repeated infection+ tranformation into squamous epithelium)

Question 4

Sites of congenital cholesteatoma

Answer 4

Middle ear
Petrous apex
Cerebellopontine angle

Question 5

Effects in congenital cholesteatoma

Answer 5

Conductive hearing loss (behind tympanic membrane)

Discharge (spontaneous rupture)(confused with CSOM)

Question 6

Genesis of primary acquired cholesteatoma

Answer 6

Invagination of pars flaccida (negative pressure cause retraction pocket accumulates keratin debris)

Basal cell hyperplasia (proliferation of pars flaccida)(childhood infection)(attic formation)

Squamous metaplasia (attic under metaplasia of keratinizing squamous epithelium)(subclinical infection)

Question 7

Secondary acquired cholesteatoma

Answer 7

Pre existing perforation (postero suerior marginal / large central) in pars tensa

Migration of squamous epithelium in middle ear (involve tympanic annulus)(allow ingrowth of squamous epithelium)

Metaplasia (infection)(via pre existing perforation)

Question 8

Expansion of cholesteatoma in bone

Answer 8

Enters middle ear cleft by path of least resistance
Enzymatic bone destruction (collagenase, acid phosphatase, proteolytic enzymes)

Attic extend backwards in aditus, antrum, mastoid, mesotympanum, incus, head of malleous.

Destruction of ear ossicles, erosion (bony labyrith, facial nerve canal, sinus plate, tegmen tympani