A cholesteatoma is an abnormal, non-cancerous skin growth that develops in the middle ear, the air-filled space directly behind the eardrum. This growth functions like a cyst or sac and is composed of keratinizing squamous epithelium, the same type of skin that lines the ear canal. Its location within the delicate structures of the ear makes prompt diagnosis and treatment important.
Understanding Cholesteatoma
A cholesteatoma is a collection of misplaced skin cells and keratin debris that forms a sac behind the eardrum, typically located in the middle ear or adjacent mastoid bone. Although it is not a tumor, its behavior can be destructive to surrounding tissues. The accumulation of dead skin cells within the sac causes the growth to slowly expand in size.
This expansion creates pressure and releases enzymes that erode the delicate structures of the middle ear and temporal bone. The growth can destroy the tiny hearing bones, called the ossicles, and may affect the bone separating the ear from the brain.
How Cholesteatomas Develop
Cholesteatomas develop in two primary ways: acquired or congenital, with acquired being far more common. The most frequent cause of an acquired cholesteatoma is chronic malfunction of the Eustachian tube, the passage that ventilates the middle ear. When the Eustachian tube does not open properly, negative pressure forms in the middle ear space. This pressure pulls a small, weakened area of the eardrum inward, creating a retraction pocket.
Skin cells that normally exit the ear canal become trapped in this pouch, where they shed and accumulate, eventually forming the cholesteatoma. Chronic ear infections can also weaken the eardrum membrane, contributing to this process. A congenital cholesteatoma is present at birth, forming when skin cells are trapped in the middle ear during fetal development. Congenital cholesteatomas are typically identified in early childhood.
Recognizing the Signs
Patients typically notice symptoms when the growth becomes large enough to cause problems. The most common early sign is a persistent ear discharge with a foul odor, known as otorrhea. This discharge results from the trapped skin cells and debris becoming chronically infected.
Progressive hearing loss, often in only one ear, is a frequent symptom caused by the growth interfering with the sound-conducting bones of the middle ear. Patients may also report a feeling of fullness or pressure inside the affected ear.
In more advanced cases, the growth may extend deeper, leading to severe symptoms. Dizziness or a spinning sensation (vertigo) can occur if the cholesteatoma erodes into the inner ear. Rarely, the condition can cause facial muscle weakness or paralysis if it damages the facial nerve.
Medical Confirmation and Imaging
Diagnosis begins with a thorough history and physical examination of the ear. Using an otoscope or microscope, the physician examines the eardrum for a retraction pocket, a visible mass, or pearly-white debris. Suctioning the ear canal may be necessary to clear discharge and obtain a clear view of the eardrum and middle ear space.
An audiogram, or hearing test, is conducted to objectively measure the effect on hearing. This test determines the extent of hearing loss and whether it is conductive, which is typical for cholesteatoma. The results are an important factor in planning subsequent treatment.
Imaging studies are necessary to determine the full extent of the disease and plan for surgery. A high-resolution Computed Tomography (CT) scan is the preferred modality. The CT scan shows the size of the cholesteatoma and identifies bony defects or erosion into the surrounding temporal bone and mastoid air cells.
Treatment and Management
The definitive treatment for cholesteatoma is surgical removal, as the growth cannot be eliminated with medication. The primary goals of surgery are to eradicate the disease completely, create a safe and dry ear, and attempt to preserve or restore hearing function. The surgical approach depends on the size and location of the growth and often involves a mastoidectomy, which removes diseased air cells from the mastoid bone.
A surgeon may also perform a tympanoplasty to repair or reconstruct the eardrum and hearing bones damaged by the growth. For extensive disease, the canal wall-down technique offers the highest probability of complete removal but leaves a cavity requiring regular cleaning. For less extensive growths, the canal wall-up technique preserves normal ear anatomy but carries a higher risk of recurrence.
Long-term post-operative management is important due to the persistent nature of the condition. The risk of the growth persisting or recurring often necessitates a follow-up “second-look” surgery, typically scheduled 6 to 12 months after the initial procedure. Regular check-ups with an ear specialist are necessary for many years to monitor for any signs of recurrence.