Definition:
- Abnormal extension of keratinizing squamous epithelium into the middle ear and mastoid air cell spaces.
Clinical Presentation:
- Initially asymptomatic.
- Conductive hearing loss.
- Intermittent ear discharge.
- Changes on otoscopic examination, most commonly superior and posterior, showing a retraction pocket with or without debris, granulation tissue, or granular polyp.
- Advanced cases may present with facial nerve weakness, vertigo, inner ear invasion, or intracranial infection.
Examination:
- Otoscopy reveals a perforation or retraction pocket of the tympanic membrane.
- Always examine the facial nerve function.
Pathogenesis:
Congenital Cholesteatoma:
- Arises from embryonal nests of epithelial cells.
- Typically presents at ages 4-5, more common in males.
- Appears as a spherical white mass behind an intact tympanic membrane.
- Causes conductive hearing loss.
Acquired Cholesteatoma:
- More common in adults.
- Often originates from a retraction pocket within the tympanic membrane due to underlying Eustachian tube dysfunction or recurrent otitis media.
- Keratin accumulates in this sac, rarely from the migration of skin cells through a perforation.
- Grommets may offer some protection.
- Proteolytic enzymes produced by the keratinizing squamous epithelium can destroy the incus, stapes, and cochlea, extending to balance centers and leading to complications like abscess and mastoiditis.
- The condition can threaten the tegmen (bony plate separating the middle ear from the cranium).
- Hearing loss occurs as ossicles are engulfed, although some sound transmission might persist.
- Acute infection can lead to otorrhea; if otitis media fails to resolve with antibiotics, suspect cholesteatoma.
Differential Diagnosis:
- Osteoma of the ear canal.
- Tympanosclerosis (scarring).
- Other perforations and retractions (safe if centrally located and not involving the fibrous edge, with no white mass or granulation tissue).
- Malignancy of the ear canal.
Investigations:
- Audiogram: To identify conductive hearing loss; if sensorineural loss is present, suspect inner ear involvement.
- CT of the temporal bone: To assess the extent of disease and involvement of surrounding structures.
Management:
- Surgical intervention is typically required.
- Referral to an otolaryngologist for appropriate management and surgical planning is essential.
