Cholesteatoma

Cholesteatoma’s definition is skin growth in the wrong place behind the ear drum. Skin is a normal part of the ear canal and the outside part of the ear drum (tympanic membrane). When this skin grows behind the ear drum or it grows into the bone behind the ear (mastoid bone), it is called a cholesteatoma. This skin grows at a much faster rate than regular skin and destroys the structures around it. The treatment of a cholesteatoma is its removal by surgery. Close follow-up is necessary to monitor for recurrence.

You may reference the Anatomy of the Ear page for better understanding of the anatomy.

Cholesteatomas most commonly present with hearing loss and drainage from the ear. In advanced stages, facial paralysis, bleeding, or dizziness (vertigo) can be a presenting sign. Rarely, patients may present with meningitis or brain abscess from extension of the cholesteatoma into the area around the brain.

There are 3 causes of cholesteatoma

• A cholesteatoma that develops due to a retraction (suctioning in of the ear drum) in the ear drum. When eustachian tube disease is present for a long time, the ear drum can slowly get retracted (suctioned into the middle ear). Over time, the skin from the outside grows into the space behind the ear drum and into the mastoid bone. The cause of this retraction is a dysfunction in the eustachian tube (which allows air to get from the back of the nose to the space behind the ear drum). This is called a primary cholesteatoma.
• A secondary cholesteatoma can occur when the outer skin layer of the ear drum can grow into the space behind the ear drum through a perforation in the ear drum.
• A cholesteatoma can be present since birth (congenital). This means that some skin existed behind the ear drum from birth. Congenital cholesteatomas of the middle ear (space behind the ear drum) are most commonly discovered when the child is between 2-9 years old. They are most typically located in the anterior superior or posterior superior parts behind the ear drum. The next most common place for congenital cholesteatomas is in the skull base or petrous apex. These lesions are usually discovered in adulthood as they grow slowly and will eventually place pressure on the brain or the nerves around the brain (cranial nerves). Rarely, congenital cholesteatomas can occur in the mastoid.

Generally after a complete history and physical exam, some tests need to be performed to diagnose and plan for the treatment of cholesteatomas. A test of the hearing (audiogram and tympanogram) and CT scan (special x-ray) of the temporal bone (ear bone) is necessary for diagnosis and planning of treatment. If there is a question on what the lesion is made of, an MRI may be obtained with a special sequence called diffusion weighted imaging (DWI) that can distinguish cholesteatoma from non-cholesteatoma tissue.

As the cholesteatoma grows, it destroys the bone and other structures around it. The most common structures that are invaded by the cholesteatoma include the hearing bones of the ear (ossicles), which causes hearing loss, inner ear (which would cause complete deafness and dizziness), the facial nerve (which would cause weakness or facial paralysis), or invade the bone covering the brain and cause meningitis or brain abscess. If left untreated, these complications will occur with time.

Initial treatment with antibiotic drops help in reducing the infection burden that causes the drainage. However, the bulk of cholesteatoma is dead skin cells which cannot be penetrated by the immune system and ear drops. Therefore, the only definitive treatment is surgery. This generally requires an incision inside the ear canal or in the back of the ear or in the ear canal to get access to the area of the cholesteatoma. Many surgeons perform a second surgery 6 to 12 months after the first surgery to ensure that the cholesteatoma has not recurred and for reconstruction of hearing. Our philosophy is to try to do the surgery for removal and hearing reconstruction in one setting. We have been able to reduce the need for second surgeries to 5-10-%. Due to the presence of infection at the first surgery, sometimes, hearing reconstruction is performed at the second surgery. If we are able to do the reconstruction in one setting, we can see the hearing results at 4 months and if satisfactory, we will not perform a second surgery. We use MRI with coronal DWI (HASTE sequence) for monitoring of recurrence of cholesteatoma. This prevents the need for a second surgery in over 90% of the patients. The MRI is generally repeated yearly for 3 years and a possible last one at 5 years.

The use of Otoendoscopy (small angled cameras) has been shown to significantly reduce the chance of recurrence after surgery for cholesteatomas. The chance of recurrence of cholesteatomas was reduced from nearly 50% to 5%. In a study to be published by Dr. Djalilian and his colleagues, it was found that otoendoscope use reduced the need for more radical surgery. In addition, we routinely obliterate the mastoid cavity so a large radical cavity is not created. This allows the patient to continue to participate in water sports. Areas that are around corners that are usually not visible with a microscope can be visualized with endoscope and cholesteatomas can be removed from those locations. At UC Irvine, otoendoscopy (in addition to a microscope) is used routinely in the removal of cholesteatomas for a less invasive approach. Dr. Djalilian was invited to speak at the American Neurotology Society meeting on the novel use of a curved laser in addition to otoendoscopy for treatment of cholesteatoma. Dr. Djalilian has also published the first study on the use of a curved Argon laser which allows for removal of disease from around corners.