Cholesteatoma

Tympanic membrane — The tympanic membrane is also called the eardrum. It separates the outer ear from the middle ear. When soundwaves reach the tympanic membrane they cause it to vibrate. The vibrations are then transferred to the tiny bones in the middle ear. The middle ear bones then transfer the vibrating signals to the inner ear. The tympanic membrane is made up of a thin connective tissue membrane covered by skin on the outside and mucosa on the internal surface.

Definition

Cholesteatoma is a type of skin cyst located in the middle ear.

Causes, incidence, and risk factors

Cholesteatoma can be a birth defect (congenital), but it more commonly occurs as a complication of chronic ear infection.

Poor function in the eustachian tube leads to negative pressure in the middle ear. This pulls a part of the eardrum (tympanic membrane) into the middle ear, creating a pocket or cyst that fills with old skin cells and other waste material. The cyst can become infected. The cyst may get bigger and break down some of the middle ear bones or other structures of the ear, affecting hearing, balance, and possibly function of the facial muscles.

Symptoms

Signs and tests

An ear exam may show a pocket or perforation (opening) in the eardrum, often with drainage. The deposit of old skin cells may be visible with a microscope or an otoscope, a special instrument to view the ear. Sometimes a mass of blood vessels may be seen in the ear.

The following tests may be performed to rule out other causes of dizziness.

CT scan
Electronystagmography

Treatment

Surgery is needed to remove the cyst.

Expectations (prognosis)

Cholesteatomas usually continue to grow if not removed. Surgery usually works, but you may occasionally need the ear cleaned by a health care provider. Additional surgery may be needed if the cholesteatoma comes back.

Complications

Brain abscess
Deafness in one ear
Dizziness (vertigo)
Erosion into the facial nerve (causing facial paralysis)
Labyrinthitis
Meningitis
Persistent ear drainage
Spread of the cyst into the brain

Calling your health care provider

Call your health care provider if ear pain, drainage from the ear, or other symptoms occur or worsen, or if hearing loss occurs.

Prevention

Prompt and complete treatment of chronic ear infection may help to prevent some cases of cholesteatoma.

References

Chole RA, Sudhoff HH. Chronic otitis media, mastoiditis, and petrositis. In: Cummings CW, Flint PW, Haughey BH, et al, eds. Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2010:chap 139.

Review date:: August 3, 2010
Reviewed by:: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Seth Schwartz, MD, MPH, Otolaryngologist, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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