What Is Cholesteatoma?
Cholesteatoma is the presence of abnormal stratified squamous epithelium in the middle ear and temporal bone in the place of normal mucosa of the middle ear compartment, which has the capacity to progress and destroy the middle and inner ear structures.
It begins as skin-like growth or sac. With time this growth collects dirt and causes infection. It expands and destroys the normal structures of the middle ear and inner ear like ossicles, facial nerve, cochlea, and semicircular canals. It acts basically as a locally present malignant growth.
What Are the Types of Cholesteatoma?
There are two main types;
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Congenital cholesteatoma.
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Acquired cholesteatoma.
What Is Congenital Cholesteatoma?
It arises from the embryonic epidermal cell resting in the middle ear cleft or temporal bone. Congenital cholesteatoma occurs at three important sites:
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Middle ear.
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Petrous apex.
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Cerebellopontine angle.
It produces symptomatology depending on its location and is usually seen in the pediatric age group.
What Is Acquired Cholesteatoma?
Middle ear cholesteatoma is otherwise called acquired cholesteatoma. They are closely related to the temporal bone's tympanic membrane and pneumatized portion. Most acquired cholesteatoma arises from the middle ear infection, leading to the tympanic membrane's perforation.
What Are the Symptoms of Acquired Cholesteatoma?
Patients with acquired cholesteatoma usually have hearing loss and purulent, foul-smelling continuous discharge from the ears usually accompanied by ear pain, blood-stained ear discharge, etc. Other symptoms may include;
- Facial nerve dysfunction.
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Perilymphatic fistula.
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Cochlear fistula.
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Inner ear deafness.
What Is the Pathology of Acquired Cholesteatoma?
Cholesteatoma is a middle ear and mastoid disease characterized by the accumulation of keratinizing stratified squamous epithelium that results in local inflammation and destruction.
They are composed of densely packed desquamated keratinizing squamous cells arising from the peripheral shell facing the epithelium inward. As the cells mature, they continue to grow into a mass slowly. There are four categories,
- Invagination of Negative Pressure:
This growth results from the eustachian tube dysfunction and tympanic membrane retraction with keratinization and debris deposition at the neck.
- Invasion or Migration:
With the help of the previous perforation setting, the keratinized cells invade the middle ear.
- Basal Cell Hyperplasia and Papillary Ingrowth:
Hyperplasia is the growth of cells. It is the invasive hyperplasia of the basal cell layer of the tympanic membrane due to infection.
- Metaplasia:
This results in chronic irritation of the middle ear.
What Are the Radiographic Features of Acquired Cholesteatoma?
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Computed Tomography (CT):
CT has been the primary choice of diagnosis. CT scan demonstrates the bony structure of temporal bone, and cholesteatoma appears as a region of soft-tissue attenuation, exerting mass effect and resulting in bony erosion.
Finding depends on the site of arising:
a. Pars flaccida expands into prussak space, eroding the scutum and displacing the ossicles medially. At the same time, inferior extension is less common and is most frequently seen in children.
b.Pars Tensa: In the posterosuperior region extends medial to the incus and displaces the ossicle laterally, anterior and inferior.
2. Magnetic Resonance Imaging (MRI):
As CT cannot determine granulation tissue, scarring, and recurrent cholesteatoma, it is used as a postoperative diagnostic method. MRI uses strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body; therefore, it can generate accurate pictures of the acquired cholesteatomas. In the MRI scan, cholesteatoma is shown as,
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T1: Low signal.
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T2: High signal.
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T1 C+ (Gd): No enhancement.
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DWI: Diffusion restriction.
How Is the Pathogenesis for Cholesteatoma Demonstrated?
New theories for pathogenesis (progression of the disease) are proposed. The following theories are proposed to discuss the pathogenesis of cholesteatoma:
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Mucosal traction (set of mechanisms).
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Selective epitympanic dysventilation approach.
Mucosal Traction Theory:
In the theory of mucosal traction, adhesions of opposing mucosal surfaces exert traction on the tympanic membrane, stimulating cytokine production (cytokines are an essential part of the inflammatory process and are produced by several immune cells) and keratinocyte proliferation (growth of the cells).
Selective Epitympanic Dysventilation Theory:
The theory of selective epitympanic dysventilation tells that retraction (the action of drawing something back or back in) of the pars flaccida occurs secondary to block of ventilation pathways between the mesotympanic space and the epitympanic compartment. The eustachian tube ventilates the remaining mesotympanic space. The selective epitympanic dysventilation theory explains how epitympanic cholesteatoma can be associated with a well-ventilated and normal-appearing pars tensa.
What Is the Treatment and Prognosis of Acquired Cholesteatoma?
Cholesteatoma has to be removed surgically. The different surgical techniques are,
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Anteroposterior approach.
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Posterior tympanotomy.
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Combined approach tympanoplasty.
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Modified radical mastoidectomy.
Surgical planning for cholesteatoma with a microscopic and endoscopic ear examination. The recent approach also includes endoscopic management. Endoscopy provides accurate visualization of portions of the middle ear that are not seen with a microscope. These regions have the attic, sinus tympani, anterior epitympanic rim, protympanum, and hypotympanum. Firstly, the microscope cleans the ear and looks through the tympanic membrane. Secondly, the ear is then examined with an endoscope. The endoscopic examination supplies a panoramic view of the entire tympanic membrane with improved visualization of the anterior tympanic rim and pars flaccida.
What Is the Differential Diagnosis?
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Cholesterol Granuloma: Cholesterol granulomas are rare, benign (noncancerous) cysts that can occur at the tip of the petrous apex, a part of the skull next to the middle ear. The cysts are expanding masses that contain fluids, lipids, and cholesterol crystals, surrounded by a fibrous lining.
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Mucoid Impaction: Otherwise known as mucus plugging, it is referred to as an airway filled by mucoid secretions that can be obstructive and non-obstructive.
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Glomus Tympanicum: It is a type of tumor and is also known as paraganglioma.
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Facial Nerve Schwannoma: They are rare benign tumors originating from the facial nerve. They show symptoms including facial spasms, paralysis or palsy, and hearing loss.
Conclusion:
A cholesteatoma is a cyst-like growth behind the eardrum or involving the eardrum. It is common in people with recurring ear infections and eustachian tube problems. Early detection and treatment can help avoid hearing loss. It is essential to have a regular follow-up.
