Cholesteatoma

Cholesteatoma is an expanding collection of keratinising stratified squamous epithelium (keratin debris) within the middle ear and mastoid. It lies in a sac lined by matrix with an underlying inflammatory perimatrix. It is locally destructive rather than neoplastic.

Incidence is about 3 to 15 per 100,000 per year, with a peak in children and young adults (a more aggressive course in children) and a slight male predominance.

It erodes bone through pressure, enzymatic activity (collagenase, matrix metalloproteinases) and osteoclast stimulation by cytokines (interleukin-1, tumour necrosis factor alpha).

Types:

• Acquired primary: retraction pocket of the pars flaccida in the attic, or of the posterosuperior pars tensa, from chronic Eustachian tube dysfunction and negative middle ear pressure.
• Acquired secondary: migration of squamous epithelium through a perforation, or implantation after trauma or surgery.
• Congenital: an epithelial rest behind an intact tympanic membrane, seen in children with no history of otitis media or previous ear surgery.

Complications:

• ossicular erosion with conductive hearing loss (the incus long process is typically eroded first)
• erosion of the lateral semicircular canal (labyrinthine fistula)
• facial nerve palsy (the tympanic segment is dehiscent in about 50 percent)
• tegmen erosion with meningitis, brain abscess or extradural abscess
• sigmoid sinus thrombosis
• labyrinthitis with sensorineural hearing loss
• subperiosteal (postauricular) abscess and Bezold abscess
• petrositis

• Chronic or recurrent painless otorrhoea, typically scanty, foul smelling and resistant to topical treatment. Granulation tissue or polyp in the ear canal.
• Progressive conductive hearing loss, and sometimes sensorineural loss when the labyrinth is involved.
• Aural fullness; occasionally otalgia, headache and tinnitus.
• Vertigo, especially with pressure change (fistula test positive, from lateral canal fistula), and nystagmus.
• Facial weakness, fever, severe headache, or neck stiffness indicates intracranial or extratemporal complications.
• Otoscopy: attic retraction pocket or crust, white keratin flakes or pearly mass behind the drum, marginal or attic perforation, granulations, and canal wall erosion.

• Otomicroscopy is the cornerstone, with cleaning of the ear under the microscope to see the pocket depth and the matrix.
• Pure tone audiometry with air bone gap, tympanometry, and tuning fork tests. Bone conduction thresholds assess cochlear involvement.
• High resolution CT of the temporal bone shows a soft tissue mass in the epitympanum or mesotympanum with blunting of the scutum, ossicular erosion, widening of the aditus, mastoid involvement, and erosion of the tegmen, semicircular canal, fallopian canal or sigmoid plate. It informs the surgical plan.
• Non-echo-planar diffusion weighted MRI (with T1 and contrast) is the best test to detect residual or recurrent cholesteatoma (as small as 3 mm, bright signal on diffusion weighted imaging without enhancement) and to identify intracranial complications.
• MRI is used for follow up in closed cavity (canal wall up) surgery.
• Swab culture (Pseudomonas aeruginosa, Staphylococcus aureus, Proteus, anaerobes), and cranial imaging when intracranial complications are suspected.

Management is surgical, aimed at eradication of disease, creating a safe dry ear, and preserving or restoring hearing.

• Medical therapy is adjunctive only. Aural toilet (microsuction) and topical antibiotic steroid drops (ciprofloxacin 0.3 percent with dexamethasone 0.1 percent, 4 drops twice daily for 7 to 10 days) dry the ear before surgery.
• Treat infection with systemic antibiotics if there is cellulitis or complications (amoxicillin clavulanate 625 mg three times daily; or ciprofloxacin 500 mg twice daily for Pseudomonas). Avoid ototoxic drops with a perforation (aminoglycosides) when possible.
• Surgery: tympanomastoidectomy.
  • Canal wall up (intact canal wall): preserves anatomy and a normal ear canal. It has a higher recurrence rate (about 10 to 40 percent), so planned second look surgery at 6 to 12 months or MRI surveillance is needed.
  • Canal wall down (modified radical or radical mastoidectomy, with removal of the posterior canal wall and creation of an open mastoid bowl, with meatoplasty): better access with lower recurrence (about 5 to 10 percent). It is used for extensive disease, in a sole hearing ear, or in cases with poor follow up. It requires lifelong cavity care and risks dizziness with caloric stimulation and water.
  • Endoscopic ear surgery (transcanal) for attic and mesotympanic disease allows minimal bone removal.
  • Ossiculoplasty (partial or total ossicular replacement prosthesis, titanium or autograft) at the same sitting or as a delayed stage, and tympanic membrane reconstruction with temporalis fascia or cartilage.
• Complications management: urgent mastoidectomy with decompression for facial palsy.
• Labyrinthine fistula: preserve the matrix over the fistula or seal with bone pate, fascia.
• Subperiosteal abscess: incision and drainage with mastoidectomy.
• Intracranial complications: high dose intravenous ceftriaxone 2 g twice daily with metronidazole 500 mg every 8 hours, neurosurgical drainage, and mastoidectomy. Add vancomycin in cases of suspected resistant organisms.
• Congenital cholesteatoma: complete excision (often transcanal), in children at an early stage when localised.
• Follow up: clinical review at 3 and 6 months, then annually for at least 5 years (up to 10 years). Diffusion weighted MRI at 12 months (and again at 3 to 5 years) after canal wall up surgery. Audiometry at 3 to 6 months after surgery.
• Prevention of recurrence: management of Eustachian tube dysfunction (grommet insertion), early treatment of retraction pockets (observation with audiology review, or cartilage reinforcement), and avoiding water entry into mastoid cavities.