Cholesteatoma

• Acquired cholesteatoma, the common form, follows chronic eustachian tube dysfunction: persistent negative middle ear pressure draws the tympanic membrane into a retraction pocket, usually in the pars flaccida, which accumulates desquamated keratin. Chronic otitis media and perforation are the usual antecedents.
• Congenital cholesteatoma appears as a white mass behind an intact tympanic membrane in a child with no history of ear disease.
• The characteristic presentation is painless, chronic, foul-smelling otorrhoea that does not resolve with topical or oral antibiotics, with progressive conductive hearing loss from ossicular erosion. Otoscopy shows a retraction pocket, granulation tissue or a pearly white mass.
• Bone erosion drives the complications, and they are the reason this matters: ossicular destruction, labyrinthine fistula with vertigo, facial nerve palsy, mastoiditis, and intracranial extension causing meningitis, brain abscess or sigmoid sinus thrombosis.
• CT of the temporal bones defines the extent and bony erosion; surgery (tympanomastoidectomy) is the only definitive treatment, and medical therapy alone is never sufficient.

Mechanism 1 — primary acquired (retraction pocket)

• Chronic eustachian tube dysfunction: sustained middle-ear negative pressure retracts the pars flaccida into Prussak's space. The pars flaccida lacks the fibrous middle layer of the pars tensa, so it is the first part of the drum to collapse. This is the commonest pathway.

Mechanism 2 — secondary acquired (epithelial migration)

• Marginal or attic perforation from chronic suppurative otitis media, through which canal squamous epithelium migrates medially.
• Trauma or iatrogenic implantation: temporal bone fracture, tympanostomy tube placement, myringoplasty or prior middle-ear surgery seeding keratinocytes behind the drum.

Mechanism 3 — congenital

• Failure of involution of the epidermoid formation, an embryonic squamous rest in the anterosuperior mesotympanum, producing a white mass behind an intact drum in a child with no otologic history.

Modifiable risk factors

• Recurrent acute otitis media and chronic otitis media with effusion: repeated inflammation scars and obstructs the eustachian tube.
• Tobacco smoke exposure (including secondhand), biofilm-laden adenoid hypertrophy and untreated allergic rhinitis — all impair tubal opening and mucociliary clearance; smoking cessation and adenoidectomy are targeted at this axis.
• Prior ear surgery/tube placement and unprotected water exposure with a perforation.

Non-modifiable risk factors

• Craniofacial anomalies: cleft palate (abnormal tensor veli palatini insertion) is the classic stem detail; also Down syndrome and Turner syndrome, where narrow, hypotonic eustachian tubes give near-universal middle-ear disease.
• Age and sex: acquired disease peaks in older children and young adults; congenital disease presents in preschoolers, with a male predominance.
• Family history of chronic ear disease and prior temporal bone trauma.

From tubal dysfunction to keratin sac

• Negative middle-ear pressure: a non-ventilating eustachian tube allows mucosal gas absorption, and the resulting vacuum retracts the compliant pars flaccida into the epitympanum.
• Keratin trapping: normal tympanic epithelium migrates laterally and self-cleans. Once invaginated, desquamated keratin cannot escape the pocket's narrow neck, so the sac enlarges progressively — the process is self-perpetuating and irreversible without removal, which is why no medical therapy cures it.

Why it destroys bone

• Two-component architecture: a matrix of keratinising stratified squamous epithelium over a perimatrix of inflamed subepithelial granulation tissue. The perimatrix, not the keratin itself, drives destruction.
• Osteoclast activation: perimatrix fibroblasts and inflammatory cells release IL-1, TNF-α and RANKL, plus matrix metalloproteinases and collagenase, producing enzymatic osteolysis; expanding keratin adds pressure necrosis of adjacent bone.
• Hyperproliferative epithelium: the matrix shows increased basal-cell proliferation and cytokeratin patterns resembling skin under wound-healing stress, explaining relentless growth despite benign histology.

Why the clinical picture looks as it does

• Painless foul otorrhoea: avascular keratin is an ideal culture medium and is unreachable by systemic antibiotics; Pseudomonas aeruginosa and Proteus produce the malodour. Because infection sits in dead debris rather than inflamed periosteum, there is little pain — the discharge simply recurs after each antibiotic course.
• Conductive hearing loss: the long process of the incus has the most tenuous blood supply and erodes first, discontinuing the ossicular chain; the stapes superstructure follows. A sac bridging an eroded gap can transmit sound, so hearing is occasionally near-normal early — a classic trap.
• Directional spread: growth into the lateral semicircular canal creates a labyrinthine fistula (vertigo), over a dehiscent tympanic facial nerve segment causes palsy, and superiorly through the tegmen or posteriorly to the sigmoid sinus produces intracranial disease.

Symptoms

• Painless, chronic, scanty, foul-smelling otorrhoea unresponsive to topical and oral antibiotics: infected avascular keratin debris; the absence of pain distinguishes it from acute otitis media and otitis externa.
• Progressive conductive hearing loss: ossicular erosion, usually beginning at the long process of the incus. Hearing may be deceptively preserved if the keratin sac itself bridges the eroded chain.
• Aural fullness and tinnitus from the mass and middle-ear dysfunction.
• Vertigo or disequilibrium, especially on pressure changes, nose-blowing or sneezing: implies a labyrinthine fistula, most often of the lateral semicircular canal — a red flag, not a routine feature.
• Facial asymmetry: erosion over a dehiscent tympanic segment of CN VII producing peripheral facial palsy — urgent.
• Headache, fever, altered mental status or worsening pain: intracranial extension until proven otherwise.

Examination findings

• Otoscopy/microscopy: a retraction pocket or crust in the pars flaccida (attic) filled with white keratin flakes; a pearly white mass behind or through the drum; friable granulation tissue or an aural polyp that bleeds on contact. An attic crust that will not clear should be lifted under the microscope — a pocket hides beneath it.
• Congenital variant: a discrete white mass in the anterosuperior quadrant behind an intact drum, in a child with no otorrhoea, perforation or prior ear surgery.
• Tuning forks: Weber lateralises to the affected ear and Rinne is negative (bone > air) on that side — conductive pattern.
• **Positive fistula test (Hennebert sign)**: nystagmus or vertigo when tragal pressure or pneumatic otoscopy is applied, indicating a labyrinthine fistula.
• Postauricular tenderness, swelling or a protruding auricle: coalescent mastoiditis or subperiosteal abscess.

Step 1 — clinical, under magnification

• Otomicroscopy or otoendoscopy is the initial diagnostic test: cholesteatoma is diagnosed by direct visualisation of keratin in a retraction pocket, a pearly mass or granulation with debris. Debridement of attic crust under the microscope is both diagnostic and therapeutic. Any chronically draining ear with an attic retraction warrants otolaryngology referral rather than another antibiotic course.

Step 2 — quantify the functional deficit

• Pure-tone audiometry with air and bone conduction: shows a conductive loss with an air–bone gap; a gap that widens over serial audiograms suggests progressive ossicular erosion. A sensorineural component implies inner-ear involvement (fistula or labyrinthitis) and raises urgency.
• Tympanometry: flat (type B) tracing with normal canal volume if the drum is intact; an abnormally large volume indicates perforation. Preoperative audiometry is required for surgical planning and medicolegal documentation of baseline hearing.

Step 3 — imaging

• High-resolution CT of the temporal bones without contrast is the confirmatory anatomic study: a non-dependent soft-tissue mass with bone erosion — blunting of the scutum, ossicular (especially long process of incus) erosion, lateral semicircular canal fistula, facial canal dehiscence, tegmen tympani or sigmoid plate defects. CT cannot reliably distinguish cholesteatoma from granulation tissue or effusion; it maps bone and surgical anatomy.
• Non–echo-planar diffusion-weighted MRI is the imaging test that is specific for keratin: cholesteatoma shows restricted diffusion (bright on DWI) whereas fluid, granulation and scar do not. It is the standard tool for detecting residual or recurrent disease, increasingly replacing routine planned second-look surgery.
• Add contrast-enhanced MRI when intracranial complication is suspected.

Step 4 — definitive

• Histopathology of the excised specimen: keratinising stratified squamous epithelium (matrix) enclosing lamellated keratin debris, over an inflamed perimatrix.
• Staging: the EAONO/JOS joint consensus uses the STAM system (S = difficult-access sites, T = tympanic cavity, A = attic, M = mastoid) to assign stages I–IV, which correlate with recurrence and hearing outcomes.

Immediate priorities (complicated disease is a surgical emergency)

• Facial nerve palsy, vertigo/labyrinthine fistula, meningitis, brain or epidural abscess, or sigmoid sinus thrombosis: admit, obtain contrast-enhanced imaging, start empiric IV antibiotics with CNS penetration and antipseudomonal coverage (e.g., a third/fourth-generation cephalosporin such as ceftazidime or cefepime plus metronidazole; add vancomycin per IDSA bacterial meningitis guidance, dosed to a 24-hour AUC/MIC of 400–600 per the 2020 IDSA/ASHP consensus), and proceed to urgent mastoidectomy with neurosurgical input.

Preoperative medical therapy — adjunctive only

• Aural toilet under the microscope plus topical fluoroquinolone drops (e.g., ciprofloxacin–dexamethasone otic) to dry a discharging ear before surgery. AAO-HNS guidance for a non-intact tympanic membrane favours non-ototoxic quinolone drops; aminoglycoside-containing drops are avoided because of cochleovestibular toxicity through an open middle ear.
• Medical therapy never eradicates cholesteatoma. Antibiotics treat the superinfection, not the keratin sac; "another course of amoxicillin" is the wrong answer.

Definitive management — surgery

• Tympanomastoidectomy with complete removal of the matrix is the only cure, with ossiculoplasty for hearing reconstruction (often staged).
• Canal wall up (intact canal wall): preserves the ear canal and avoids a mastoid bowl, but carries a higher residual/recurrence rate — requires planned second-look surgery or surveillance non-EPI DWI MRI.
• Canal wall down: lower recurrence, used for extensive disease, labyrinthine fistula, only-hearing ear or unreliable follow-up; creates a mastoid cavity needing lifelong cleaning and water precautions.
• Endoscopic ear surgery is increasingly used for limited attic/mesotympanic disease.
• Address the underlying eustachian tube dysfunction: adenoidectomy, tympanostomy tubes for the contralateral ear, allergy and smoke-exposure control.

Contraindicated or wrong

• Observation of a documented cholesteatoma, ototopical aminoglycosides through a perforation, blind office polypectomy (risk of avulsing an eroded stapes or exposed facial nerve), and unprotected water exposure.

Intratemporal (from bone erosion)

• Ossicular erosion: long process of incus first; presents as a widening air–bone gap and worsening conductive loss.
• Labyrinthine fistula: erosion into the lateral semicircular canal. Signalled by vertigo on pressure/pneumatic otoscopy (positive fistula test, Hennebert sign) and any sensorineural component on audiometry. Urgent — a breached labyrinth can progress to suppurative labyrinthitis and dead ear.
• Facial nerve palsy: erosion over a dehiscent tympanic segment; ipsilateral peripheral (forehead-involving) weakness in a chronically draining ear. Emergency surgical decompression/removal.
• Coalescent mastoiditis and subperiosteal abscess: postauricular swelling, tenderness, protruding auricle. Bezold abscess tracks into the neck through the mastoid tip.
• **Petrous apicitis (Gradenigo syndrome)**: otorrhoea + retro-orbital pain (V1) + CN VI palsy with diplopia.

Intracranial (all emergencies)

• Meningitis — most common intracranial complication; fever, headache, neck stiffness.
• Epidural, subdural or temporal-lobe/cerebellar abscess — focal deficits, seizures, depressed consciousness.
• Sigmoid/lateral sinus thrombosis — spiking (picket-fence) fevers, headache, sometimes Griesinger sign (postauricular oedema over the mastoid emissary vein); diagnose with contrast MRV/CT venography.
• Otitic hydrocephalus — raised intracranial pressure with papilloedema after sinus thrombosis.

Complications of treatment

• Residual disease (matrix left behind) and recurrent disease (a new retraction pocket) — the reason for second-look surgery or surveillance non-EPI DWI MRI, particularly after canal wall up procedures.
• Sensorineural hearing loss or dead ear from drilling near or manipulating the stapes/fistula.
• Iatrogenic facial nerve injury — the most feared surgical complication; intraoperative monitoring is standard.
• Chorda tympani injury causing ipsilateral taste disturbance; vertigo from labyrinthine trauma; CSF leak from tegmen dehiscence.
• Mastoid bowl problems after canal wall down: chronic debris accumulation, recurrent infection, caloric-induced vertigo on cold water exposure, and lifelong water precautions.

• The buzzword triad: painless, chronic, foul-smelling otorrhoea that recurs despite antibiotics + progressive conductive hearing loss + a pearly white mass or attic retraction pocket on otoscopy. Pain is against the diagnosis and suggests acute otitis media/externa or an evolving complication.
• Single best next step after otoscopy: audiometry plus high-resolution CT of the temporal bones to define bony erosion and surgical anatomy — then refer for tympanomastoidectomy. Not another antibiotic course.
• The one association examiners test: chronic eustachian tube dysfunction — so the stem plants cleft palate, Down syndrome, or years of recurrent otitis media with tubes.
• Ossicle to know: the long process of the incus erodes first (poorest blood supply), producing the air–bone gap.
• Pars flaccida, not pars tensa: primary acquired disease starts in the attic (Prussak's space) because the pars flaccida lacks the fibrous middle layer.
• **Vertigo or nystagmus provoked by pressing the tragus (Hennebert sign / positive fistula test) = labyrinthine fistula** of the lateral semicircular canal — urgent surgery, and a reason to choose canal wall down.
• Facial nerve palsy in a chronically draining ear is cholesteatoma until proven otherwise — never call it Bell palsy.
• Surgery is the only cure. Topical fluoroquinolone drops and aural toilet are adjuncts to dry the ear before operating; aminoglycoside drops are avoided through a non-intact drum.
• Distractors to avoid: normal or near-normal hearing does not exclude cholesteatoma (the sac can bridge an eroded ossicular chain); a congenital cholesteatoma sits behind an intact drum with no otorrhoea history; and MRI's role is non-EPI diffusion-weighted imaging for residual/recurrent keratin (restricted diffusion), not for initial bony mapping.