Contents
Benign collections of keratinized squamous epithelium within the middle ear.
- Commonly characterized as “skin in the wrong place”
History:
The French anatomist Du Verney first reported a case of cholesteatoma-like symptoms in 1683. Nearly a century and a half later, in 1829, Cruveilhier described the pathologic features of what he referred to as pearly tumor (tumeur perlée), referring to its whitish pearly appearance. The term cholesteatoma (chole = cholesterol; steat = fat; oma = tumor) did not appear in the literature until 1838, when Johannes Müller, a German anatomopathologist, coined the term to describe a tumor that appeared “greasy in nature”. Other denominations were also proposed, including “margaritoma” by Graigie in 1891 and “keratoma” by Schuknecht in 1974; however, they were never widely adopted. Today, the term “cholesteatoma” remains the dominant term in clinical practice. Nonetheless, this is something of a misnomer because the lesion contains neither cholesterine nor fat, and it is not neoplastic in nature.
Classification
Congenital cholesteatomas:
Derived from remnants of epithelium trapped behind the tympanic membrane during development
Acquired cholesteatomas:
Result of pathologic changes that cause the uncontrolled growth of squamous keratinized epithelium in the middle ear.
- Retraction pocket cholesteatoma “primary acquired cholesteatoma”
- Pars flaccida cholesteatoma (attic cholesteatoma)
- Pars tensa cholesteatoma
- Combination of pars flaccida and pars tensa cholesteatoma
- Non retraction pocket cholesteatoma:
- Cholesteatoma secondary to chronic tensa perforation “secondary acquired cholesteatoma”
- Transplanted cholesteatoma following trauma/otologic procedures
Unclassifiable cholesteatoma
Pathophysiology
Cholesteatoma results from the enzymatic activity of the cholesteatoma matrix. This abnormal growth is locally invasive and capable of causing the destruction of structures in the middle ear cleft. Furthermore, squamous epithelium may be rendered destructive in an environment of chronic infection, thereby enhancing the osteolytic effects of cholesteatoma. Owing to the fatal capacity of intracranial complications, cholesteatomas remain a cause of pediatric morbidity and death for those who lack access to advanced medical care
- Squamous metaplasia theory: Inflammation causes mucosal lining of the middle ear to become hyperproliferative.
- Migration theory: Squamous epithelium from outer layer of TM migrates through a perforation through the drum and into the middle ear
- Basal hyperplasia theory: Basal cells of TM proliferate and move medially through the basement membrane into the middle ear
- Retraction pocket theory (M/widely accepted): Retraction pocket inton middle ear cavity results in cholesteatoma
Clinical features
Patients often present complaining of foul-smelling discharge, hearing loss, and pain that has lasted for months to years.
- Painless otorrhea (classic presentation): Scant purulent discharge that may be foul smelling
- Conductive and/or sensineural hearing loss (due to ossicular damage and tympanic membrane perforation): Often permanent and severe
- Cholesteatoma hearer: Patient with discontinuous ossicular chain still hears due to sound conducted through cholesteatoma
- Dizziness
- Pain prior to episodes of purulent discharge (sign of advanced disease)
Complications
- Sigmoid sinus thrombosis
- Conductive hearing loss
- Meningitis
- Epidural abscess
Diagnosis
Direct otoscopic examination:
Examination of the tympanic membrane to evaluate for acquired cholesteatoma should include inspection of the pars flaccida
- Round, white, compressible lesion under tympanic membrane (pathognomic)
Hearing evaluation:
Audiometry should always be done prior to surgery to establish a baseline. The speech reception threshold, air, and bone conduction and speech discrimination scores should be noted.
High-resolution computed tomography (HRCT):
CT has been the standard modality as it does provide for the ability of identifying bony changes. Owing to excellent ability of spatial resolution, CT has a high sensitivity but low specificity in the case of a mass lesion because it may be misinterpreted as granulation tissue, cholesterol granuloma or other soft tissue neoplasms. However, CT has limited value in the post-operative period due to the high negative predictive value when it shows a well-aerated, disease free middle ear and mastoid with no evidence of soft tissue present
- Sharply marginated and expansile soft tissue lesion
- Retraction of TM
- Scutum blunting and erosion of tympanic tegmen and ossicles
- Loss of normal aeration within pneumatized areas of temporal bone with bony destruction
Diffusion weighted imaging MRI (DWI-MRI):
Valuable in detection of cholesteatoma as advantages exist over CT such as a shorter examination time than delayed contrast material-enhanced imaging and no need for a contrast media injection prior to the examination. More useful after surgery
- Isointense on T1
- Hyperintense on T2
- Do not enhance with gadolinium contrast
Tissue biopsy:
Diagnosis requires a combination of squamous epithelium, granulation tissue and keratinaceous debris.
PTAM system:
Division of tympanomastoid space into protympanum (P), tympanic cavity (T), attic (A) and mastoid (M) in order to represent the extent of cholesteatoma
EAONO/JOS staging system:
European Academy of Otology and Neurotology in collaboration with the Japanese Otological Society (EAONO/JOS) working group devised this staging system which applies to four categories of middle ear cholesteatoma: pars flaccida cholesteatoma, pars tensa cholesteatoma, congenital cholesteatoma, and cholesteatoma secondary to a tensa perforation. The utility of this system is that it may be used for evaluating initial pathology in a standardized fashion and for standardization in reporting of surgical outcomes throughout the otologic community.
- Stage I: Localized cholesteatoma
- Stage II: Cholesteatoma involving two or more sites.
- Stage III: Cholesteatoma with extracranial complications or pathologic conditions
- Stage IV: Cholesteatoma with intracranial complications
Austin classification for ossicular status:
- Malleus handle present, stapes superstructure present (60%) | M+ S+
- Malleus handle present, stapes superstructure absent (23%) | M+ S-
- Malleus handle absent, stapes superstructure present (8%) | M- S+
- Malleus handle absent, stapes superstructure absent (8%) | M- S-
Differential diagnosis:
- Middle ear osteoma
- Suppurative otitis media
- Tympanosclerosis: Hyalinization of fibrous connective tissues of TM and middle ear, followed by calcification that may result in degraded hearing. In comparison to cholesteatoma, tympanosclerosis presents as hard white plaques with an irregularly sharp edge as opposed to the smooth, rounded and curved edge of cholesteatoma
Management
The definitive treatment for cholesteatoma is surgical removal of the disease to provide a safe and dry ear. Patients often present with debilitating pain and hearing loss, and it is very important to explain that the goal of surgery is cholesteatoma removal and this may not restore the patient’s hearing to normal. In fact, the patient’s hearing could decline after surgery, and it is important to discuss this possibility with the patient. Audiograms should be obtained before and after surgery.
Antibiotic-steroid therapy:
Required for patients with signs of acute infection (e.g., otorrhea) to reduce the occurrence of inflammation and granulation tissue
- Fluoroquinolones (ciprofloxacin or levofloxacin): Empirical antibiotic therapy against possible infection by Pseudomonas aeruginosa, Staphylococcus aureus, or anaerobic bacteria recommended
Tympanomastoidectomy:
Ensures removal of all cholesteatoma
- Canal wall up (CWU) mastoidectomy: Removal of all mastoid air cells while maintaining the integrity of contours in the ear canal
- Canal wall down (CWD) mastoidectomy: Removing bony posterior canal wall to create a common cavity which combines ear canal and mastoid.
- Each has advantages and disadvantages, but the canal wall down procedures result in lower rates of recurrence but require lifelong mastoid cleaning for the patient.
Tympanoplasty:
Hearing interventions:
Secondary role of cholesteatoma surgery is to either maximize hearing or restore serviceable hearing whenever possible. The management of hearing impairment depends on the type of hearing loss and the degree to which hearing can be restored. For instance, patients with minimal to no hearing loss may not require further hearing interventions.
- Hearing aids (for sensorineural hearing loss)
- Ossiculoplasty (for conductive hearing loss caused by destruction of ossicles): Through autologous grafts (e.g., bone or cartilage) or a prosthetic device (e.g., partial or total ossicular replacement prosthesis PORP/TORP)