Epitympanic cholesteatoma

Case contributed by Dr Alasdair Grenness

Presentation

One week of purulent and bloody right otorrhea on a background on intermittent otorrhea over the past 6 months

Patient Data

Age: 30 years
Gender: Female

30 year old female of South Asian descent referred to the emergency department by her general practitioner over concern of fungal otitis externa. She presented with a week of bloody and purulent right otorrhea not improving with topical antibiotics. She reported two previous episodes of otorrhea within the last 6 months. There was no history of previous ear disease or surgery. Upon toileting of a large amount of purulent debris and skin from the ear canal, evaluation of the tympanic membrane could be made and a conductive hearing loss confirmed on tuning fork testing. 

Photo

There is clear erosion of the superior aspect of the ear canal into the attic of the middle ear with what appears to be moist keratin. The head of the malleus appears to be eroded. The pars tensa of the tympanic membrane appears intact and the chorda tympani appears unaffected. It is difficult to establish where the pars flaccida currently is positioned. 

Such appearance of otoscopy is pathognomonic for cholesteatoma (classically epitympanic) with concurrent otitis media(likely chronic supporative otitis media). 

Further management involves first treating the localized infection with topical anitbiotics. Second an audiogram should be performed to establish the degree of hearing loss associated. Finally a CT PTB is arranged to establish extent of disease and for surgical planning rather than diagnosis.  

CT

Complete opacification of the right epitympanic space including Prussak's space. The anterior aspect of the right epitympanic space appears expanded and there is erosion of the anterior portion of the scutum (correlate with clinical photographs above). There is also erosion of the malleus head and long process of the incus.  The tegmen tympani appears intact. 

The mastoid is poorly pneumatized, sclerotic and fully opacified, an indicator of long standing middle ear disease. The cochlea, vestibule, semicircular canals and facial nerve canal appear intact. 

Imaging confirms epitympanic cholesteatoma.

Case Discussion

Cholesteatomas are epidermal inclusion cysts of typically of the temporal bone in either the ear canal, middle ear, mastoid or petrous apex. They contain desquamated debris, mainly keratin, from their keratinizing squamous epithelial lining. They do not contain large amounts of cholesterol, but rather their yellow-white keratin flakes resemble cholesterol crystals 1

Diagnosis is typically made on clinical examination. However, imaging modalities such as high-resolution CT and MRI can suggest the presence of cholesteatoma and complement the clinical examination 1-3. Diffusion-weighted MRI has been shown to be a reliable technique for the detection of temporal bone cholesteatoma and is used when clinical surveillance of cholesteatoma is no longer possible (classically after reconstruction surgery post cholesteatoma removal) 3

High-resolution CT is useful for operative planning and recommended before both primary and revision surgery. Eradication is currently only possible with surgical resection. Primary treatment goals include removal of all disease. Reconstruction of damaged hearing mechanisms usually happens at a second stage procedure. Surgical approaches range from attitcotomy (transcanal), canal wall up mastoidectomy (whereby the mastoid is resected to gain access to the middle ear but the posterior canal wall is left intact) or canal wall down mastoidectomy (whereby the posterior canal wall is drilled away to give greater access to the middle ear) 2.

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