Cholesteatoma: A Perplexing Disease of the Ear

Your ear has been draining for the last 2 to 9 months, you’re not exactly sure, but it’s been quite a while.  It’s yellowish, smells like your feet and your family has been bugging you to get it checked out and fixed, since the site and smell ruins their appetites at the dinner table.  You also notice your hearing isn’t the same; in fact, your angered spouse is tired of repeating herself over and over and over…well, you get the picture.  As time passes, the ear is beginning to hurt.  Your spouse drags you to your primary care doctor who you haven’t seen in the past seven years (you forgot about that annual follow up),  She takes a look into your ear, shakes her head uttering the word, “huh,” and refers you to an ENT doctor.  After round after round of telephone calls, authorizations and pre-authorizations, appeals, etc. with the insurance company, you finally get to see the ENT doctor who after cracking a few not-so-funny jokes, announces with a little too much enthusiasm that you have a cholesteatoma.  “A what?” you ask before the excitement overcomes the giddy ENT doc.  Such an odd-sounding ailment.  This leaves you scratching your head, or your draining ear.

So what is a cholesteatoma?  This term is actually a misnomer, for there is no cholesterol and though the suffix “-oma” means “tumor,” this also is not a tumor.

A cholesteatoma forms from either a defect such as a perforation (hole) or retraction pocket in the tympanic membrane (ear drum).  The tympanic membrane is comprised of several layers of different tissue types, and the most lateral (outer) part is lined with tissue called squamous epithelium.  This is the same tissue that lines the skin on the rest of your body.  The outer layer of squamous epithelium naturally sloughs and falls off the body into the environment.  The cells of course are microscopic so you won’t notice this natural sloughing.  However, if this occurs within a deep retraction pocket on the tympanic membrane or on the edges of a perforation on the membrane, this squamous epithelium may accumulate where the cells group together as a mass.  As more sloughing occurs, this mass can grow in size and can progress medially (inward) from its source of origin. 

Upon examining the ear, one may find a pearly white material or mass in the ear.  Sometimes there is drainage of varying quality and consistency (purulent yellow, mucoid grayish, serous clear to amber fluid, bloody drainage or if mixed with ear wax, brownish or blackish) that may hide the cholesteatoma until the ear is debrided and suctioned, typically under a microscope.  Less common is swelling behind the ear in the area of the mastoid.  Sometimes a foul odor is noted due to bacterial or fungal involvement.

Though a cholesteatoma is not a tumor, it can act as one by the way it destroys surrounding tissue as just described.  For some odd reason, a cholesteatoma creates and releases osteolytic enzymes, substances that eat away at bone.  As the figure shows, a cholesteatoma can spread to other areas of the ear and beyond the ear.  Some of the structure are listed below with their potential effects:

-Mastoid air cells located behind the ear (behind the auricle or outer ear—you know, those funnel shaped objects on each side of your head): this can lead to bone destruction and infection in the mastoid called mastoiditis (where the tissue behind the ear become red and swollen and painful, causing the auricle to protrude forward).

-Ossicles (the bones of hearing connecting the tympanic membrane to the cochlea): results in further hearing loss (more specifically, conductive hearing loss, which is a result of sound not properly being transmitted from the tympanic membrane to the ossicles to the cochlea).  This sometimes is reversible with surgery and reconstruction of the ossicular chain.

-Cochlea or inner ear: this leads to a sensorineural hearing loss, which often is permanent.  In addition, tinnitus may occur, resulting in hearing ringing or other various noises in your ear.  Also dizziness can occur since the cochlear shares fluid channels with the labyrinth below.

-Labyrinth: this is a collection of fluid-filled sacs and semi-circular canals and helps with you balance and sense of equilibrium.  If a cholesteatoma erodes into this structure, dizziness in the form of vertigo (spinning or movement sensation), off-balance and sometimes nausea and vomiting can occur.  And since the labyrinth communicates with the cochlea, sensorineural hearing loss and tinnitus also can occur.

-Tegmen: the part of the base of skull separating the top of the ear from the brain.  If a cholesteatoma violates this plate of bone and inflames the meninges, meningitis occurs, resulting in fevers, headaches, neck pain and neck stiffness.  If it progresses further into the brain, a brain abscess can develop.

-Jugular vein and transverse sinus: the jugular vein runs through the mastoid.  This particular portion of the vein is called the transverse sinus.  Cholesteatoma involving this structure can lead to a clot or thrombus, blocking flow of blood downward.  This clot could extend further down the jugular vein lower in the neck.  These thrombi (plural form of thrombus) can also become infected, which can lead to sepsis (blood born infection leading to other parts of the body).  If parts of the thrombus dislodged, they can travel further down towards the heart and from their pumped to other areas of the body.  These dislodged clots are known as emboli (plural of embolus).

Treatment centers on removing the cholesteatoma.  If the cholesteatoma is small or confined to a limited area, cleaning the sloughed material away may suffice, but regular follow-ups are needed to prevent recurrence.   However, many situations require surgery to remove the cholesteatoma along with any devitalized or infected structures damaged in the process.  This often requires a mastoidetomy (drilling out the mastoid bone through an incision behind the auricle) along with surgery of the tympanic membrane and ossicles.  If possible, reconstruction of the ossicles can be done to improve conductive hearing loss.

Thus, for persistent ear symptoms such as drainage, chronic pain, hearing loss and particularly if you have balance or dizziness along with those ear symptoms, have the ear fully evaluated to rule-out an underlying cholesteatoma.  Have that smelly, draining ear treated correctly and restore sanity to the family dinner table.

©Randall S. Fong, M.D.