Cholesteatoma is an expanding growth in the middle ear that destroys bones of the middle ear (ossicles) and can become infected, resulting in chronically draining ears. Cholesteatomas are not considered tumors, but their expansive growth can result in a spread into the mastoid and through the base of the skull into the brain.
Types of Cholesteatoma
Cholesteatoma can be a rare congenital cholesteatoma or more commonly an acquired cholesteatoma. Acquired cholesteatoma results from recurrent otitis media (ear infections), untreated middle ear fluid collections or an untreated perforated eardrum. The middle of a cholesteatoma cyst becomes chronically infected. If untreated, a cholesteatoma will grow and can be very destructive of the bone of the ear.
A congenital cholesteatoma is less common than an acquired cholesteatoma (commonly only around 2% of overall cholesteatoma cases), with an increase in awareness and research, has come a ratio increase of between 3.7-24%. These cysts can only be considered as congenital if they meet the following criteria:
- A mass which is medial to the tympanic membrane
- A normal tympanic membrane
- No previous history of ear surgery, ear discharge or perforation.
The tympanic membrane forms part of the hearing organ, vibrating in response to soundwaves. This is what forms the eardrum between the inner and outer ear. Over time, if this growth is left unhindered, it can significantly reduce hearing quality or ability.
These types of cholesteatomas occur in three major places: the middle ear, the petrous apex and the cerebellopontine angle. These growths are normally found deep toward the front of the ear drum.
Most often in cases of cholesteatomas, keratin builds up in a small area of tympanic membrane and increases in size until it impacts the middle ear space. The invagination of the tympanic membrane occurs through one of these particular methods:
- Wittmaack’s Theory: The cholesteatoma is formed by the retraction of the tympanic membrane from the attic or part of the pars tensa (one of the two elements that make up the eardrum) that causes retraction pockets
- Ruedi’s Theory: When infection occurs, the cells in the germinal layer of skin multiply and form squamous epithelial cells that harden into the cholesteatoma
- Haberman’s Theory: When a pre-existing perforation is present, a cholesteatoma can be formed through the epithelium (the outer layer of skin) from the meatus (passageway) or outer drum surface and grow into the middle ear
- An acquired cholesteatoma can also arise after an implantation following external trauma to the ear.
Causes of Cholesteatoma
The two major causes of acquired cholesteatoma are
- A response to infection in the middle ear
- The result of a poorly functioning eustachian tube
The eustachian tube is the tube that carries air from the back of the nose to the middle ear, the purpose of which is to equalize air pressure and keep the ear pathways clear. The result of a poorly functioning eustachian tube due to a cold, sinusitis or something similar is a partial vacuum created in the ear (the popping sensation experienced when your ear is blocked due to a change in air pressure). Over time, the vacuum pressure sucks in a pouch or sac by stretching the eardrum, especially areas weakened by previous infections. This can develop into a sac and become a cholesteatoma.
Symptoms of Cholesteatoma
Some of the following symptoms may occur when a cholesteatoma is present:
- Ear Drainage: The ear may release fluid with a foul-smelling odor
- Ear Pressure: As the cholesteatoma pouch increases in size, it may present feelings of fullness or excess pressure in the ear
- Hearing Loss: As the cholesteatoma affects the tympanic membrane, it can cause hearing loss
- Facial Pain: An ache behind or pain behind or in the ear can be a cause of great discomfort
- Dizziness or Muscle Weakness: This can occur on one side of the face (the side where the infection is present).
Cholesteatoma is a treatable condition but is serious nonetheless, and can only fully be diagnosed by a medical examination. In addition, the cholesteatoma can cause bone erosion, which can result in a spread of the infection to the inner ear and even the brain. If left untreated, more serious symptoms can be total deafness, brain abscess, and meningitis.
In most cases, a laboratory test or incisional biopsy is not needed for diagnosis of the cholesteatoma. Most of the diagnoses are made through physical examination and radiologic findings. The usual method of radiological diagnosis is through the use of CT scans; the reason for this is that this technology has the ability to detect subtle bone defects. Prior to surgery, it is important to take measurement of a patient’s ability to hear and his/her sensitivity to sound (audiometry). In addition, air and bone conduction, speech reception threshold and speech discrimination should be measured and determined before proceeding with the surgery. MRI scans can also be used in diagnosis of cholesteatoma, but usually in the case where very specific problems are detected. When any of the following are suspected in a patient, a doctor will use an MRI to further determine problems and plan treatment:
- Inflammation of the facial nerve or membranous labyrinth(fluid-filled nerves containing receptors for equilibrium and hearing)
- Brain herniation into the mastoid cavity
- Subdural or epidural abscess
- Invasion or involvement of the dura
Treatment for Cholesteatoma
Once an initial exam has been performed and a doctor or surgeon confirms the presence of a cholesteatoma, a doctor may proceed with treatment in one of the following ways primarily:
- Careful cleaning of the ear
- Antibiotics to kill infection
- Ear drops
A doctor must also assess the growth traits of a cholesteatoma. If the cholesteatoma is found to be large, it will require surgery, under general anesthetic, to remove the risk of serious complications.
The complication of surgery is the risk it poses to a patient’s bone structure and regular function within the ear. Often the treatment for a cholesteatoma consists of at least two surgeries, one to remove the cholesteatoma, and the second, to check that the growth is gone completely and that the structure of the inner ear is intact.
The nature of this condition is that it is progressive and potentially very harmful to other tissues located close to the ear. In light of this, when approaching treatment for cholesteatoma, priority is given to extraction before the desire to retain basic hearing. If the disease can be removed simply, the ossicles (auditory bones) are usually able to be preserved. However, if the disease is more complicated, it may be necessary to remove the involved ossicles to ensure full recovery from the cholesteatoma, and this is usually recommended.
Diagnosis and Treatment
If you have recently had an ear infection and seem to be experiencing symptoms of a cholesteatoma, or are concerned about yourself or your child, contact your physician immediately and seek a referral for immediate diagnosis and early treatment.
Dr. Rohn and Dr. Gamble are ear, nose, throat, and sinus surgeons with offices located in Plano and Dallas. If you would like to schedule an appointment with our office, please call our Plano office at 972-378-0633 or Dallas office at 214-239-1641.