Choleteatoma

Choleteatoma

Choleteatoma

Cholestesteatoma="Skin hn d wrong place"

it has 2 parts

a=matrgx
-made of keratinised squamous epithlm resting on d thin stroma of fibrous tissue

b=central white mass
-consisting of keratin debris produced by matrix
also caled epidermosis/keratoma

* Origin of cholestma

1=presence of congenital cell rests

2=invagination of tympanic membrne 4m d attic in form of retraction pocket=Wittmaacks theory

3=basal cell hyperplasia. The basal cels of germinal layer of skin proliferate due 2 infection=Ruedis theory

4=epithelial invasion. The epithelium 4m d meatus grows in2 middle ear through a pre-existing perforation=Habermans theory

5=metaplasia. Middle ear mucosa undergoes metaplasia due 2 repeated perforation and convert in2 squamous type=Sades theory

* Classification

1. Congenital

- arises 4m d embryonic epidermal cell
- sites: middle ear,petrous apex,cerebellopontine angle
- presents as white mass behind d intact tympanic membrane and causes conductive hearing loss

2. Acquired primary

- there is primary bcos there no history of previous otitis media/perforation
- theories :

a. invagimation of pars flaccida
- persistent -ve pressure in d attic causes a retraction pocket which accumulate keratin debris
b. basal cell hyperplasia
c. squamous metaplasia

3. Acquired secondary

- there is already pre-exisisting perforation in d pars tensa
- always asociated with d posterosuperior marginal or sometimes central perforation

- theories :

a. migration of squamous epithelium
b. metaplsia

* Expansion of cholestoma

- 4m d middle ear invade d surrounding structure and follows d path of least resistance and then enzymatic bone distruction
- attic cholstoma may extends backwards 2 aditus,antrum,mastoid, downward in2 mesotympanum and medialy surrounds d incus

* Distruction of bone

- cholstoma has d property 2 distroy bone e.g. ear occicles, bony labyrinth, canal of facial nerve, sinus plate, tegman tympani