What it is
A cholesteatoma is a collection of keratinizing squamous epithelium — ordinary skin — that has become trapped inside the middle ear or mastoid. Skin continuously sheds dead cells. On the outside of the body those cells simply fall away, but inside a closed space they accumulate, forming an enlarging sac of debris.
The problem is not the material itself but what it does mechanically and biologically. As the sac expands it erodes surrounding bone, and it tends to become chronically infected, which accelerates that erosion. Left alone, a cholesteatoma will progressively destroy the structures around it.
Most cholesteatomas are acquired, developing when the eardrum retracts inward — typically as a consequence of long-standing Eustachian tube dysfunction — and forms a pocket that traps shed skin. A minority are congenital, present from birth as a white mass behind an otherwise intact eardrum, and these are often found in children during an unrelated ear exam.
Symptoms
- Persistent drainage from the ear, often with an unpleasant odor, that keeps returning despite treatment
- Hearing loss on the affected side, usually gradual and conductive
- A feeling of pressure or fullness in the ear
- Dizziness or vertigo, which can indicate erosion into the inner ear
- Facial weakness, which is uncommon but significant, and indicates the cholesteatoma has reached the facial nerve
Some cholesteatomas cause remarkably few symptoms until they are quite extensive, which is why an ear that drains repeatedly deserves a careful look even when it is not particularly painful.
Why it is treated
The concern with cholesteatoma is its complications, which follow from its capacity to erode bone:
- Erosion of the ossicles, the middle ear bones, causing conductive hearing loss
- Erosion into the inner ear, producing a labyrinthine fistula with vertigo and sensorineural hearing loss
- Exposure or injury of the facial nerve, which runs through the middle ear
- Erosion through the bone at the top of the ear, risking a cerebrospinal fluid leak, meningitis, or intracranial infection
These outcomes are uncommon with timely treatment, and they are the reason treatment is recommended rather than watchful waiting.
Diagnosis
Diagnosis usually begins with otoscopy or microscopic examination of the ear, which may show a retraction pocket, a pearly white mass behind the eardrum, or granulation tissue and drainage. An audiogram documents the type and degree of hearing loss.
CT of the temporal bone shows the extent of the disease and which structures have been eroded, and is used for surgical planning. MRI, particularly diffusion-weighted sequences, is useful for distinguishing residual or recurrent cholesteatoma from scar tissue and fluid in a previously operated ear.
Surgical treatment
Surgery removes the cholesteatoma and creates an ear that is safe and dry. The specific operation depends on how far the disease has spread.
Tympanomastoidectomy is the general term for removing cholesteatoma from the middle ear and mastoid. Within that, the main decision is whether to preserve the back wall of the ear canal — a canal wall up approach, which maintains normal ear canal anatomy but carries a higher chance of residual disease — or to remove it — a canal wall down approach, which creates an open mastoid cavity that is easier to inspect but requires ongoing cleaning. The choice depends on the extent of disease, the anatomy, and how reliably follow-up can be arranged.
Ossiculoplasty, reconstruction of the hearing bones, addresses the conductive hearing loss. It is sometimes done at the same operation and sometimes staged to a second procedure, once the ear is known to be free of residual disease.
Follow-up
Cholesteatoma requires long-term follow-up. Residual disease — small fragments left behind — and recurrent disease from a new retraction pocket are both possible, and both are far easier to manage when found early. Follow-up combines periodic examination with imaging or, in some cases, a planned second-look procedure.