A cholesteatoma is a destructive growth composed of skin cells that develops abnormally within the ear. This growth typically occurs in the middle ear space, the air-filled cavity behind the eardrum, and can extend into the mastoid bone, the honeycombed structure behind the ear. Although it is not a true tumor, the accumulation of shed skin cells and keratin debris forms an expanding mass with erosive properties. This mass slowly destroys the delicate structures of the middle and inner ear.
How Cholesteatoma Develops
Cholesteatoma formation is categorized into two main types: acquired and congenital. Acquired cholesteatomas are the most common, often arising from chronic eustachian tube dysfunction. When the eustachian tube malfunctions due to chronic infection or allergies, it fails to equalize pressure, causing negative pressure to build up in the middle ear.
This negative pressure causes a part of the eardrum to collapse inward, creating a retraction pocket. Since the outer layer of the eardrum is skin, this pocket collects shed skin cells that cannot be cleared from the middle ear. As this debris-filled sac expands, it becomes a cholesteatoma, releasing enzymes that break down surrounding bone and soft tissue.
Congenital cholesteatomas are a rarer form of the condition, present from birth, and are not related to prior ear infections or eardrum retraction. They result from tiny remnants of embryonic skin cells trapped behind an intact eardrum during fetal development. These growths are usually discovered when they become large enough to cause symptoms, often in children between two and five years old.
Recognizing the Symptoms
A persistent discharge from the ear, known as otorrhea, is a characteristic sign, often having a foul odor. This unpleasant smell is caused by bacterial infection developing within the trapped, decaying skin debris of the growth. This drainage often continues despite courses of antibiotics intended to treat a simple ear infection.
Progressive hearing loss is another common symptom, usually conductive in nature, meaning sound waves are blocked from reaching the inner ear. This loss occurs as the expanding cholesteatoma damages or disrupts the ossicles. Patients may also experience a feeling of pressure or fullness within the affected ear. While pain can occur, especially if an acute infection is present, the condition is often painless in its early stages, which can delay diagnosis.
Diagnostic Procedures
Confirming a suspected cholesteatoma begins with a thorough physical examination using an otoscope or specialized microscope. The professional looks for a visible white or yellowish mass, a retraction pocket in the eardrum, or a perforation with debris. Clearing discharge from the ear canal is necessary to fully visualize the eardrum and the extent of the growth.
Following the physical exam, a hearing test (audiometry) is conducted to determine the type and degree of hearing loss and confirm the conductive hearing loss associated with the disease. High-resolution Computed Tomography (CT) scans of the temporal bone are then performed to precisely map the extent of the cholesteatoma within the middle ear and mastoid. The CT scan is crucial for surgical planning as it reveals bone erosion, such as damage to the ossicles, but it cannot always distinguish the growth from soft tissue like scar tissue.
Treatment Options and Recovery
Surgical removal is the treatment for a cholesteatoma because medication, such as antibiotics, can only temporarily control an infection and cannot eliminate the underlying growth. The primary goals of surgery are to completely eradicate the disease, create a safe and dry ear, and, when possible, reconstruct damaged middle ear structures to preserve or improve hearing. The operation, often a mastoidectomy combined with tympanoplasty, is performed under general anesthesia.
The surgeon must remove all cholesteatoma tissue, often involving drilling out infected air cells within the mastoid bone. Depending on the extent of the disease, the procedure may be a canal wall-up technique, which preserves the ear canal wall, or a canal wall-down technique, which removes it for better access and disease control. If the ossicles have been destroyed, the surgeon may attempt to reconstruct the ossicular chain during the same procedure or a secondary operation.
Recovery involves careful post-operative management, including keeping the ear dry for several weeks to allow the surgical site to heal. Follow-up appointments are essential for cleaning the ear and monitoring for any recurrence of the growth. For patients who undergo the canal wall-up procedure, a “second-look” surgery is often recommended six to twelve months later to visually confirm that no residual cholesteatoma cells remain.