01OverviewDefinition, clinical context and the essential points that orientate the chapter.
The normal outer surface of the eardrum and ear canal sheds skin outwards. Cholesteatoma develops when keratinising tissue becomes trapped in a location where this process no longer clears it effectively. Material accumulates and the surrounding inflammatory process can damage nearby structures. The name is misleading if interpreted as a cancer or simply a deposit of cholesterol: the clinically important feature is misplaced, progressively accumulating squamous tissue.
Patients often present after repeated treatment for a smelly discharging ear, but a relatively quiet ear may still contain significant disease. A short course of drops can improve the infected component and leave the underlying lesion untouched. This is why treatment response must not cancel referral when the drum remains suspicious. The consultation should explain both the need to create a safe ear and the separate, less predictable goal of hearing improvement.
Key points
- Cholesteatoma is keratinising squamous tissue in an abnormal middle-ear or mastoid location, not a malignant tumour.
- Despite being non-neoplastic, it can erode nearby bone and cause serious complications.
- Recurrent offensive discharge and conductive hearing loss are common clues, but neither is present in every case.
- Inspect the attic and posterior drum carefully, particularly when a retraction pocket contains keratin.
- Ear cleaning and antibiotics control associated infection but do not eradicate the keratinising sac.
- Most fit patients require surgery, with the approach matched to extent, anatomy and individual priorities.
- CT supports assessment of erosion and surgical anatomy; specialist diffusion-weighted MRI is especially important after surgery.
- Long-term review remains necessary because residual disease or a new retraction pocket can lead to recurrence.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Acquired retraction-pocket disease
A vulnerable area of drum can retract into the middle ear and lose its ability to clear keratin. Attic and posterior pockets are important sites to inspect when recurrent discharge or hearing loss is reported.
Acquired disease through a defect
Squamous epithelium can enter an abnormal middle-ear space in association with a perforation or previous intervention. A history of ear disease or surgery should therefore inform interpretation of new debris and discharge.
Congenital cholesteatoma
An epithelial inclusion can be present behind an intact membrane without the usual history of recurrent infection. A white middle-ear lesion in a child requires specialist assessment rather than reassurance based on an intact drum.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Keratin retention
The lining continues to produce squamous debris within a pocket or sac. Retained material can enlarge in a concealed space, explaining why the visible opening may underestimate the true extent of disease.
- 2Inflammatory bone erosion
The lesion and associated inflammation can erode the ossicles and adjacent temporal bone. Loss of protective boundaries permits damage to the inner ear, facial nerve or structures separating the ear from the brain.
- 3Residual and recurrent disease
Residual cholesteatoma results from tissue remaining after removal; recurrence can arise when a new retraction pocket develops. Both mechanisms justify follow-up even after an initially successful operation and symptom improvement.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Explore recurrent discharge, odour, hearing change and previous temporary improvement with drops. A long period of intermittent symptoms can be more informative than the appearance of the current small episode.
Look for attic or posterior retraction, white keratin, crusting and granulation. If the base of a pocket cannot be seen, document that limitation rather than declaring the ear normal.
Ask about everyday communication and new disequilibrium, then arrange formal hearing assessment. Compare symptoms with the other ear, particularly when it is the person’s better-hearing side.
Record facial movement, eye closure and mastoid findings. Severe pain, neurological symptoms or a systemically unwell patient changes the pathway from planned assessment to urgent hospital care.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Specialist otomicroscopy or endoscopic examinationFirst step - Why
- Establish the lesion and assess areas hidden during routine otoscopy.
- Interpretation and limitations
- Cleaning can reveal the entrance and character of a pocket but may not show its full extent. Findings determine whether further imaging and operative assessment are necessary.
- 02
Pure-tone audiometry - Why
- Measure baseline hearing and support consent and rehabilitation planning.
- Interpretation and limitations
- Air and bone conduction distinguish conductive from mixed loss. The audiogram informs the likely hearing benefit and the consequences of operating on an only-hearing or better-hearing ear.
- 03
High-resolution CT of the temporal bones - Why
- Map erosion, anatomical variation and the likely surgical extent.
- Interpretation and limitations
- CT is the usual first-line imaging study when imaging is needed before surgery. It provides a bony roadmap but cannot reliably distinguish every soft-tissue opacity, especially in a previously operated ear.
- 04
MRI with suitable diffusion-weighted sequences - Why
- Investigate selected diagnostic questions and detect postoperative hidden disease.
- Interpretation and limitations
- Non-echo-planar diffusion-weighted imaging, with anatomical sequences, is useful for residual or recurrent cholesteatoma. Very small lesions may be missed, so a negative study does not automatically end surveillance.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Chronic mucosal otitis media
A chronic central perforation can discharge without a keratinising lesion. Complete visualisation of the remaining drum and attic is needed before assuming that recurrent drainage is purely mucosal disease.
Wax or external keratin debris
Material lying in the canal may obscure the drum and imitate a deeper lesion. Trained cleaning and otomicroscopy establish its location; unskilled probing of a suspicious pocket risks injury.
Tympanosclerosis or a healed drum scar
White plaques may reflect scarring rather than a growing keratin sac. Their relationship to the membrane, surrounding anatomy and hearing findings helps an experienced examiner distinguish them.
An inflammatory polyp or tumour
Granulation and bleeding can conceal more than one underlying disorder. A persistent mass requires ENT examination and, when indicated, tissue diagnosis rather than an assumption of benign infection.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01Suspicious earRefer while controlling associated infectionFirst stepExamination suggests retained keratin or a concealed pathological drum pocket.+
- 1Arrange ENT assessment with a clear description of the pocket, discharge, hearing symptoms and previous ear surgery.
- 2Use trained cleaning and appropriately selected topical treatment for accompanying infection when indicated, checking membrane integrity and the exact product.
- 3Advise keeping the ear dry and avoiding manipulation while explaining which new symptoms require emergency reassessment.
- 4Retain the referral even when discharge improves, because antimicrobial response does not demonstrate removal of the keratinising lesion.
02Definitive treatmentPlan a safe ear and realistic hearing goalsDefinitiveSpecialist assessment confirms cholesteatoma and the patient is considering treatment.+
- 1DefinitiveDiscuss surgical removal as the usual definitive approach, alongside anaesthetic fitness, the other ear’s hearing and the patient’s priorities.
- 2Use examination, hearing tests and imaging to select an approach appropriate to the extent rather than applying one operation to every lesion.
- 3Explain potential hearing change, altered taste, dizziness, tinnitus and facial nerve injury, together with the possibility of further surgery.
- 4For a patient who cannot or does not choose surgery, agree specialist cleaning and infection control with explicit ongoing complication risk.
03After surgeryMaintain surveillance and rehabilitationThe lesion has been removed and postoperative recovery is underway.+
- 1Follow the surgeon’s instructions on dressings, water exposure, pressure changes and return to work, with early contact for unexpected deterioration.
- 2Check healing and hearing at planned appointments and discuss hearing rehabilitation once the postoperative ear is suitable.
- 3Use the specialist surveillance plan, which may combine clinical examination, diffusion-weighted MRI and selected second-look surgery.
- 4Explain that delayed residual or recurrent disease can occur and that new discharge, hearing decline or vestibular symptoms should prompt review.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Ossicular and cochlear injury
Damage to the sound-conducting chain commonly reduces hearing, while inner-ear involvement can cause permanent sensorineural loss. Preoperative audiometry helps distinguish these components and informs realistic counselling.
Labyrinthine fistula and vestibular dysfunction
Erosion near the bony labyrinth can produce dizziness or severe vertigo. New vestibular symptoms are a reason for urgent specialist assessment, not for repeated pressure testing in a non-specialist setting.
Facial nerve dysfunction
Inflammation or erosion around the facial nerve can cause weakness. Eye closure and corneal safety need immediate attention while ENT evaluates infection and the need for surgical intervention.
Intracranial infection
Spread across damaged temporal bone can cause meningitis or an abscess. Severe headache, meningism or neurological deterioration requires emergency multidisciplinary care and appropriate imaging.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Review the cavity or reconstructed drum at the planned ENT visits rather than relying on symptom absence alone.
- Track hearing against the preoperative baseline and assess how the person manages communication in daily life.
- Check facial function and persistent dizziness after surgery, escalating significant new or worsening symptoms.
- Ensure surveillance imaging or a planned second procedure remains booked when the patient changes care settings.
- Discuss long-term cleaning needs if the surgical approach leaves an accessible mastoid cavity.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
A small opening can hide extensive disease
The visible neck of a retraction pocket is not a reliable measure of what lies beyond it. Imaging and specialist assessment answer questions that routine otoscopy cannot.
CT and MRI answer different questions
CT is valuable for bone and operative anatomy. After surgery, nonspecific soft tissue makes CT less useful for residual disease, while the appropriate diffusion-weighted MRI protocol can identify retained keratin.
Surveillance has a long horizon
European Society of Head and Neck Radiology recommendations support postoperative MRI surveillance for at least five years where indicated. The individual schedule depends on procedure, risk and findings, and some patients still need second-look surgery.
Choose consent outcomes carefully
Eradication and a manageable ear are central aims. Hearing may improve, remain unchanged or worsen, so do not frame surgery solely as a hearing-restoration procedure.
No curative drug course exists
Topical treatment treats associated infection, with systemic therapy reserved for its own indication. Neither a successful swab result nor a dry ear means the epithelial sac has disappeared.
11Common pitfallsFrequent interpretation and management errors.
- 01
Do not dismiss a suspicious retraction pocket merely because its opening looks small.
- 02
Repeatedly treating offensive discharge without visualising the drum can delay definitive care.
- 03
Routine CT is not an adequate substitute for the appropriate postoperative diffusion-weighted MRI assessment.
- 04
Do not discharge a patient permanently after one reassuring early postoperative examination or scan.