Key Facts

Cholesteatoma is an abnormal accumulation of keratinised squamous epithelium that grows within the middle ear cleft and mastoid. Despite its benign histology, it behaves aggressively, eroding bone through enzymatic activity and pressure effects. It requires surgical management and long-term follow-up.

Epidemiology

• Incidence: 9-12 per 100,000 per year in the UK
• Peak incidence: children and young adults
• Male:female ratio 1.5:1
• More common in Caucasian populations
• Acquired cholesteatoma is far more common (98%) than congenital (2%)

Aetiology

• Acquired cholesteatoma (most common): develops from retraction pocket of tympanic membrane (usually pars flaccida/attic region)
  • Eustachian tube dysfunction → negative middle ear pressure → TM retraction → retraction pocket → accumulation of keratin debris
  • Also from TM perforation (marginal) with epithelial migration into middle ear
• Congenital cholesteatoma: keratinised epithelium behind intact TM, usually in children; thought to arise from embryonic epithelial rest
• Risk factors: chronic otitis media, recurrent AOM, Eustachian tube dysfunction, cleft palate, previous ear surgery

Pathophysiology

• Trapped squamous epithelium desquamates and accumulates keratin debris
• Growing mass exerts pressure on surrounding structures
• Cholesteatoma releases collagenases (MMP-2, MMP-9) and inflammatory cytokines (TNF-α, IL-1, IL-6)
• Enzymatic bone resorption erodes ossicular chain, tegmen tympani, semicircular canals, and facial nerve canal
• Secondary infection is common due to trapped debris
• Can create fistula into labyrinth or erode into middle/posterior cranial fossa

Typical Presentation

• Persistent foul-smelling ear discharge (otorrhoea) — typically unilateral and unresponsive to standard antibiotic treatment
• Conductive hearing loss (progressive)
• Ear fullness or discomfort
• Usually painless unless superinfected

Examination Findings

• Attic retraction pocket or crust (pars flaccida) on otoscopy — pathognomonic
• Keratin debris or polyp in the attic/posterior-superior TM
• Marginal perforation with squamous epithelium
• Granulation tissue
• Aural polyp arising from middle ear

Red Flags

• Facial nerve palsy (VII nerve erosion — urgent surgical indication)
• Vertigo or sensorineural hearing loss (labyrinthine fistula)
• Headache, meningism (intracranial complication)
• Mastoid abscess (post-auricular swelling)
• Bilateral cholesteatoma (rare, consider congenital)

Bedside

• Otoscopy: attic crust/retraction, keratin debris, marginal perforation, polyp
• Microsuction/aural toilet: to adequately visualise pathology
• Tuning fork tests: Rinne (negative on affected side), Weber (lateralises to affected ear in CHL)

Bloods

• Not routinely required
• FBC, CRP if acute infection or complications suspected

Imaging

• High-resolution CT temporal bones (non-contrast): gold standard for pre-operative planning
  • Soft tissue mass in middle ear/mastoid with bony erosion
  • Ossicular chain erosion (long process of incus most commonly affected)
  • Tegmen erosion, lateral semicircular canal fistula
  • Facial nerve canal dehiscence
• MRI (diffusion-weighted imaging): increasingly used to detect residual/recurrent cholesteatoma post-operatively (bright on DWI due to restricted diffusion in keratin)
  • Non-echo planar DWI (e.g. HASTE) preferred for small lesions
  • May reduce need for second-look surgery

Special Tests

• Pure tone audiometry: conductive hearing loss (air-bone gap)
• Tympanometry: often not possible if perforation
• Fistula test: positive if labyrinthine fistula present (caloric-type response to pressure changes)

Non-pharmacological

• Regular aural microsuction to keep cholesteatoma cavity clean
• Water precautions (keep ear dry)
• Surveillance audiometry

Pharmacological

• No medical cure — antibiotics and drops do not treat cholesteatoma itself
• Topical antibiotic drops (ciprofloxacin 0.3%) for secondary infection
• Systemic antibiotics (co-amoxiclav) for acute exacerbation or pre-operative infection control
• IV antibiotics if intracranial complications

Surgical

• Surgery is the definitive treatment — aim is complete disease removal and creation of a safe, dry ear
• Canal wall up mastoidectomy (combined approach tympanoplasty):
  • Preserves posterior canal wall anatomy
  • Better cosmetic result and water precaution avoidance
  • Higher recurrence rate (~30%) — requires second-look surgery at 9-12 months or DWI MRI surveillance
• Canal wall down mastoidectomy (modified radical mastoidectomy):
  • Creates open mastoid cavity (needs lifelong aural toilet)
  • Lower recurrence rate (~10%)
  • Used for extensive disease, revision surgery, or unreliable follow-up
• Ossiculoplasty: ossicular chain reconstruction for hearing rehabilitation (may be staged)
• Tympanoplasty: TM repair

Referral Criteria

• All suspected cholesteatoma requires ENT referral (2-week wait if malignancy concern)
• Urgent referral: facial nerve palsy, vertigo, suspected intracranial complication
• Long-term ENT follow-up: minimum 5 years post-surgery

• Recurrence/residual disease: 10-30% depending on surgical technique (higher with canal wall up)
• Hearing restoration: variable; ossiculoplasty can improve but rarely restores normal hearing
• Facial nerve palsy: occurs in <1% from cholesteatoma but is a surgical risk
• Labyrinthine fistula: present in 5-10% of cholesteatoma cases; may cause permanent SNHL
• Intracranial complications (meningitis, abscess): <2% in modern practice
• Lifelong follow-up recommended for canal wall down cavities
• MRI DWI surveillance increasingly used to monitor canal wall up cases and detect early recurrence

Cholesteatoma Complications by Structure Eroded

Canal Wall Up vs Canal Wall Down Mastoidectomy