Cholesteatoma is a special form of chronic otitis media in which keratinizing squamous epithelium grows from the tympanic membrane or the auditory canal into the middle ear mucosa or mastoid. The presence of abnormal epithelium in an abnormal location triggers an inflammatory response that can destroy surrounding structures such as the ossicles. Cholesteatomas may be congenital or acquired later in life. Acquired cholesteatomas are usually associated with chronic middle ear infection. Cardinal symptoms are painless otorrhea and progressive hearing loss. Important diagnostic procedures include mastoid process x-rays, temporal bone CT scans, and audiometric tests. Left untreated, erosion of the surrounding bone by a cholesteatoma can lead to facial nerve palsy, extradural abscess, and/or sigmoid sinus thrombosis. Therefore, even if a cholesteatoma is asymptomatic, surgery is always indicated. Surgical treatment involves tympanomastoidectomy to excise the cholesteatoma, followed by repair of the damaged middle ear structures.
- Congenital cholesteatoma
- Acquired cholesteatoma (more common)
- May be asymptomatic
- Painless otorrhea (scant but foul-smelling discharge from the affected ear)
- Occurs late in primary cholesteatoma
- Occurs early in secondary cholesteatoma
- Otoscopic findings:
- Imaging: to assess the degree of bone destruction
- Audiometry: to assess the degree of hearing loss
- Destruction of ear ossicles 
- Perilymph fistula
- Facial nerve paralysis
- Erosion of temporal bone → extradural abscess, meningitis, sigmoid sinus thrombosis
- Aural polyp
We list the most important complications. The selection is not exhaustive.