Cholesteatoma— Details & Explanations
Cholesteatoma (“Skin cyst”) of the Ear
What is a cholesteatoma?
A cholesteatoma (“co-less-tee-uh-toe-ma”) is a disorder of the ear in which the skin cells of the ear end up in the wrong place and keep growing. It is sometimes called a “skin cyst” or “skin pearl” inside the ear drum. It is a benign process (not a cancer), but it can be very destructive and therefore very serious. Treatment is surgical removal and then lifelong surveillance by an ear specialist.
What causes cholesteatoma?
Cholesteatomas can occur from multiple causes. Most commonly, they occur if the ear drum has had damage due to infection or surgery. It is often associated with a hole in the ear drum and drainage/infection. This hole could be due to prior ear infections, ear tube surgery, prior ear surgery, etc. A less common situation (5%) is that a child is born with cholesteatoma behind the ear drum; they are usually detected around 5 years of age.
What problems does cholesteatoma cause?
Cholesteatoma invades and destroys nearby structures of the ear such as the ear drum and the 3 small bones of hearing. Cholesteatomas are also associated with repeated ear infections. These infections may improve temporarily with antibiotics or ear drops, but then the infections come back. While the medicines are helpful temporarily, a surgery to remove the cholesteatoma is necessary.
As cholesteatoma grows over time, it can destroy bony structures of the ear such as:
bones of hearing (the 3 ossicles), causing hearing loss
bone protecting the facial nerve, causing a facial droop or paralysis
bone of the inner ear, causing dizziness and permanent hearing loss
bone separating the ear from the brain, causing brain exposure and infection.
How is a cholesteatoma diagnosed?
It depends. Sometimes an Ear, Nose, and Throat (ENT) doctor may look in the ear and can see the cholesteatoma. Or in a young child, a pediatrician may see a white pearly mass behind the ear drum. But sometimes it is difficult to see the cholesteatoma. In other situations where the ear has been repeatedly infected and draining, the parts of the ear are hard to see clearly and therefore the diagnosis is not made until during the surgery. An ear surgeon will look closely inside the ear, review a recent hearing test to check for ear damage, and get a CT or MRI scan of the ear. The scans help to estimate size and extent of cholesteatoma, which determines how much surgery is needed to treat the cholesteatoma.
What is the Treatment?
The treatment is surgery. The procedure is called “tympanoplasty with mastoidectomy.” Tympanoplasty includes rebuilding the ear drum. Mastoidectomy is to open the mastoid bone to clear the cholesteatoma if it has grown that far. The primary goal of the surgery is to remove all of the cholesteatoma and repair whatever damage it has caused. The secondary goal is to help the hearing. To reconstruct the delicate hearing mechanism, sometimes additional surgery is required. If the cholesteatoma happens again (see below), then additional surgery is required.
Even after a great surgery, the cholesteatoma can happen again months or years later. So the ear must be examined every 6-12 months for the rest of the patient’s life (see below).
Can cholesteatoma happen again?
Yes! The patient must understand that cholesteatoma is notorious to recur or “come back again” even after surgery. Because of this, the ear must be checked again in the future for cholesteatoma, usually 6-12 months after the surgery. This can be done with a “2nd look” ear surgery or with an magnetic resonance imaging (MRI) scan done with a specific technique called non-echo planar (NEP) diffusion weighted imaging (DWI). The “2nd look” surgery is recommended if there was a high suspicion for regrowth at the time of the first surgery.
The patient and their family must understand that cholesteatoma can “go away” for years and then “come back” years later. Therefore, even if the patient does not notice any problems, the patient MUST be seen in the office by an ear surgeon at least once a year.
What is the role of additional surgery?
It is very common for a patient with cholesteatoma to need more than one ear surgery in their lifetime. The main reasons are to remove any regrowth and/or to improve the hearing.
As mentioned above, the traditional method of checking for early regrowth was to perform a “2nd look” ear surgery about 6-9 months after the first surgery to inspect for cholesteatoma regrowth. This involves checking the sites of prior cholesteatoma (usually behind the ear drum and possibly the mastoid bone). The benefit is catching any regrowth early and removing it. The downside is that if there is no regrowth, then there might seem to be little benefit other than knowing the area is clear of cholesteatoma.
Sometimes the hearing is not good after the first surgery. Recall that the goal of the first surgery is to remove cholesteatoma and reconstruct damaged parts of the delicate ear. When the ear is infected, inflamed, or greatly destroyed by a severe cholesteatoma, it is sometimes difficult to achieve a good hearing result. In this situation, the patient would benefit from additional surgery to rebuild the hearing mechanism.
The Role of “Canal Wall Down” Surgery
In severe cases of cholesteatoma, the surgeon may perform a surgery called a “canal wall down” procedure in which the bone of the ear canal is removed. This is typically considered after multiple surgeries or if the canal wall bone has been eroded by cholesteatoma. This procedure connects the external ear canal to the hollow mastoid bone behind it.
The main benefit is that the ear is more open and can be cleared of cholesteatoma in the clinic. Thus, the patient should not require another surgery for cholesteatoma. The drawback of the ear being more open is that water and ear wax are more likely to get trapped inside the cavity of the ear, and this requires cleaning a few times a year in the clinic.