Cholesteatoma

By Marcello Cherchi, MD PhD

For patients

A cholesteatoma is a non-malignant growth that can affect the middle ear or inner ear and present with hearing loss. It is less common for it to cause disequilibrium. A cholesteatoma can sometimes be seen simply on physical examination with an otoscope. In some cases imaging (with CT or MRI or both) may be helpful in confirming the diagnosis and characterizing its extent. Patients with cholesteatomas should consult with an otolaryngologist because the treatment is surgical.

For clinicians

Overview

A cholesteatoma is a non-malignant cystic lesion composed of a matrix (consisting of keratinizing squamous epithelium on a stroma of fibrous tissue) and a central white mass (consisting of keratin debris produced by the matrix).  Cholesteatomas can arise anywhere in the temporal bone and are locally invasive.  They can occur at any age.  They usually present to an otolaryngologist when they involve the auditory canal or tympanic membrane.  They can cause conductive hearing loss (when they involve the middle ear space), sensorineural hearing loss or disequilibrium (when they invade the labyrinth).  CT and MRI give complementary imaging information to identify and characterize cholesteatoma.  Treatment is surgical.

Introduction

A cholesteatoma is a non-malignant cystic lesion composed of a matrix (consisting of keratinizing squamous epithelium on a stroma of fibrous tissue) and a central white mass (consisting of keratin debris produced by the matrix). Cholesteatomas can arise anywhere in the temporal bone and are locally invasive (Pachpande and Singh 2022).

Classification

There is debate in the literature regarding the classification of cholesteatomas (Olszewska, Rutkowska et al. 2015, Yung, Tono et al. 2017, Pachpande and Singh 2022).

Cholesteatomas can be congenital or acquired.

Congenital cholesteatomas often arise in the middle ear. Less commonly cholesteatomas occur intracranially (Moffat, Quaranta et al. 2002, McHugh 2007, Habesoglu, Balak et al. 2009), typically at the petrous apex or in the cerebellopontine angle.

Acquired cholesteatomas in turn can either be primary (arising without any clear provoking factor) or secondary (usually arising at a site affected by injury or infection).

Epidemiology

The annual incidence of cholesteatomas is 3 per 100,000 in the pediatric population, and 9.2 per 100,000 in the adult population, with a male predominance of 1.4:1. They are more common among Caucasians (Aquino, Cruz Filho et al. 2011).

Pathophysiology

Cases presenting to neuro-otology typically involve the tympanic membrane or auditory canal.

Cholesteatomas can occupy the middle ear space (resulting in conductive hearing loss) and erode into the labyrinth (resulting sensorineural hearing loss) (Stankovic 2008, Liu, Semaan et al. 2014, Gulustan, Yazici et al. 2021).

When a cholesteatoma invades the labyrinth it may also cause disequilibrium (Liu, Semaan et al. 2014), such as when it gives rise to a labyrinthine fistula (Lim, Gangal et al. 2017, Covelli, Talamonti et al. 2019, Fujiwara, Morita et al. 2022).

In some instances, cholesteatomas co-occur with fibrous dysplasia (Tochino, Sunami et al. 2004, Zanetti and Gamba 2007, Liu and Chang 2016), a disorder of bone metabolism that can affect the skull base.

Physical examination

On otomicroscopy or otoscopy a cholesteatoma usually appears as a “whitish ovoid or round friable mass with a thin wall that contains pultaceous or a macerated substance,” often in the eardrum itself, or sometimes visible behind the eardrum (Corrales and Blevins 2013).

The Figure below, from Sergi and Fetoni (Sergi and Fetoni 2010), shows a congenital cholesteatoma in a 9-year old who presented with hearing loss.

The Figure below, from Mansour and colleagues (Mansour, Magnan et al. 2018), shows an acquired cholesteatoma.

Tests

Audiometry may detect conductive or sensorineural hearing loss in an ear affected by cholesteatoma. Tympanometry may identify reduced peak immittance.

A variety of vestibular tests have been investigated in patients with cholesteatoma, including vestibular evoked myogenic potentials (Wang, Liu et al. 2009), caloric testing and rotatory chair testing (Mostafa, Shafik et al. 2013), but these tests are not considered a standard part of the workup. Video head impulse testing has been studied in cases where cholesteatoma has led to a labyrinthine fistula (Covelli, Talamonti et al. 2019, Fujiwara, Morita et al. 2022).

Imaging

There is debate regarding the kind of imaging best suited to diagnose cholesteatoma (Barath, Huber et al. 2011, Ayache, Darrouzet et al. 2012, Corrales and Blevins 2013, Steens, Venderink et al. 2016, Muzaffar, Metcalfe et al. 2017). MRI characterizes soft tissue well and thus can image the cholesteatoma itself. A temporal bone CT characterizes bone well, and thus can identify the invasiveness of the lesion. Since the two imaging modalities give complementary information, in practice they are often both checked.

After surgical treatment (see below) there is debate about how frequently to repeat imaging to monitor for recurrence.

Treatment

If a cholesteatoma is identified or suspected, then referral to otolaryngology is appropriate because treatment is surgical. Eradication of the lesion can be attempted with a canal-wall-up or canal-wall-down mastoidectomy. Reconstruction of the tympanic membrane and/or ossicular chain may help address conductive hearing loss.

References