Cholesteatoma

Cholesteatomas:

• are skin or stratified keratinising squamous epithelium growing in the middle ear (1)
• they are a greasy-looking mass or accumulation of debris that is seen in a retraction pocket or perforation.(2)
• they often take the form of a cyst or pouch that sheds layers of old skin (3)
  
  
• divided into two types (1):
  • congenital
    • presents as a pearly white mass located behind an intact tympanic membrane
  • acquired.
    • results from a retracted or perforated tympanic membrane with an ingrowth of epithelium
      
      
• aetiology :
  • the cause is unknown
  • it may result from blockage of the Eustachian tube producing a chronic negative pressure in the middle ear which would cause the tympanic membrane to be sucked inwards as a retraction pocket
  • usually, the pars flaccida is indrawn but any thin part of the pars tensa may be involved.
  • the pockets gradually expand as the skin dequamates. Invariably, they become infected and smelly
    
    
• a cholesteatoma is potentially very dangerous because local expansion may result in damage to adjacent vital structures such as dura, lateral sinus, facial nerve and the semicircular canal

Reference:

• (1) Jon E. Isaacson and Neil M. Vora.Differential diagnosis and treatment of hearing loss. Am Fam Physician 2003;68:1125-32
• (2) Cholesteatomas: Virtual classroom of the american academy of paediatrics.http://www.aap.org/otitismedia/www/vc/ear/rvw/rvw20.cfm
• (3) http://www.aap.org/otitismedia/www/vc/ear/rvw/rvw20.cfmMedical contenet of the american academy of otolaryngology—head and neck surgery (AAO-HNS).2007