Although the majority of cases of pediatric conductive hearing loss are either otitis media or otitis media with effusion, there is a large differential diagnosis including congenital or acquired cholesteatoma, branchial arch anomalies, middle ear benign and malignant tumors, and otic capsule abnormalities among others. It is important to have a basic understanding of the hearing apparatus and possible etiologies of pediatric hearing loss to be able to adequately diagnose the less than common etiologies of pediatric hearing loss. We describe an illustrative case on congenital cholesteatoma as it is one of the more common causes of pediatric conductive hearing loss besides otitis media with effusion.
An 8-year-old girl presented to her pediatrician for a well-child visit. She had no history of frequent otitis media, hearing loss, otalgia, otorrhea, or ear surgery. She passed her newborn hearing screening.
On physical examination she was noted to have normal pinna and ear canals bilaterally. Her right tympanic membrane was intact with normal landmarks and normal pneumatic otoscopy. Her left tympanic membrane was intact, but was opacified by a white middle ear mass with limited mobility (Figure 1). In the Weber test, a 512-Hz tuning fork lateralized to the left, and the Rinne test was negative.
A large whitish mass under the tympanic membrane filling the posterior/superior aspect of the middle ear.
An audiogram demonstrated normal hearing in the right ear with a left mild conductive hearing loss. Computed tomography (CT) of the temporal bones without contrast showed a left middle ear mass with a well-aerated mastoid (Figure 2).
(A) Coronal and (B) axial computed tomography views showing the soft tissue mass in the middle ear next to the ossicular chain (arrows).
A transcanal middle ear exploration was successful in removing the cholesteatoma (Figure 3), which was emanating from the cochleariform process medial to the malleus (Figure 4) and extending posteriorly to erode the long arm of the incus and the stapes superstructure. A second transcanal procedure conducted 6 months later revealed no recurrence of the cholesteatoma, and at that time an ossicular chain reconstruction was performed with a titanium prosthesis (Figure 5). After healing, repeat hearing testing confirmed restoration of hearing back to normal levels of 4 kHz.
The large cholesteatoma after elevation of the tympanic membrane and exposure of the middle ear space.
The middle ear showing (A) the cochleariform process, (B) the tensor tympani tendon, (C) the undersurface of the malleus, and (D) the residual cholesteatoma.
Titanium ossicular prosthesis in the middle ear.
The auditory pathway itself is an intricate physiologic process. The system is designed to coordinate the transmission of energy through external, middle, and inner ear structures, allowing sound wave energy to be converted into neural information that can be interpreted by the brain. To do this, sound waves are first funneled through the external ear canal and focused on the tympanic membrane. As the tympanic membrane vibrates, it sets the three ossicles of the middle ear into motion. The final ossicle—the stapes—within this chain serves as the interface between the middle and inner ear. Vibration of the stapes footplate results in fluid movement within the inner ear. This fluid wave causes hair cells within the cochlea to bend resulting in the generation of complex neural signals that are then sent to the central auditory cortex.
The system is complex, and compromising any one of the aforementioned components can result in hearing loss. To make the classification of hearing loss easier, each case can be broadly grouped into one of three main subtypes: conductive (CHL), sensorineural (SNHL), or mixed. Although rare exceptions do exist, as a general rule, disease processes affecting structures from the external canal to the stapes footplate result in CHL. Meanwhile, disease processes affecting the cochlea or cochlear nerve result in SNHL.
In the United States, an estimated 12,000 children are born each year with congenital hearing impairment.1 Early identification of these patients is crucial for successful treatment and rehabilitation. Several studies have demonstrated that failure to identify these patients by age 6 months can result in lifelong educational and socioeconomic consequences.2 Unfortunately, up until the late 1980s, children were routinely diagnosed later in life, with an average age of diagnosis between ages 2.5 and 3 years.3 In 1995, the Joint Committee on Infant Hearing recommended universal Newborn Hearing Testing (NBHT) for all US-born newborns, not just those with high-risk features.4 Since its implementation, the measure has been a resounding success, with more than 97% of newborns now being screened for hearing loss.5
The vast majority of patients with congenital hearing loss will present with SNHL identified on the NBHT. However, there are still newborns, who despite passing the NBHT, are genetically predisposed to developing progressive hearing loss (both sensorineural and conductive) in early childhood. In the case of congenital cholesteatoma, there is usually no hearing loss until the lesion grows enough to be destructive. In general, these patients will pass screenings and have normal hearing early on. They are usually not diagnosed until age 2 to 3 years.6 The physical examination conducted by primary care providers remains the front-line intervention for diagnosis and screening. A basic understanding of the epidemiology, pathophysiology, and presentation of the disease improves a clinician's ability to identify at-risk patients and to prevent complications from this destructive disease process.
Cholesteatoma is a collective term to describe abnormal skin growth within the middle ear. The condition is subcategorized into two distinct disease processes: congenital cholesteatoma and acquired cholesteatoma. Diagnostic criteria have been established to distinguish the two entities. Patients with congenital cholesteatoma must have (1) a mass medial to the tympanic membrane, (2) a normal and intact tympanic membrane, and (3) no previous history of ear discharge, perforation, or ear surgery.7 By all accounts it is a relatively rare disorder, with an incidence estimated at about .12 per 100,000 children.8
There are competing theories regarding the etiology of congenital cholesteatoma. Even though a complete discussion regarding the embryologic derivation of the disease is beyond the scope of this article, a cursory appreciation is helpful in understanding the disease pathology. The most widely accepted theory is the epithelial rest theory. The theory was originated in 1936 by Teed9 who was the first to observe epidermal appendages within the middle ear mucosa of temporal bones. This theory was further advanced by the work of Levenson et al.10 who suggested that dormant ectodermal rests were positioned within the middle ear during normal development. These rests are normally resorbed at around 33 weeks of gestation. However, when these rests remain they can proliferate and ultimately develop into a cholesteatoma. Although this remains the prevailing theory, other suggested models include the invagination theory, the metaplasia theory, and the implantation theory.
Although the precise pathogenesis remains unclear, the varying patient presentations are consistent and have been well-described. Patient's most commonly present without any significant otologic symptoms or history. However, for those with symptoms, the most common chief complaint is hearing loss. Physical examination classically reveals a pearly white lesion medial to an intact tympanic membrane in the anterior-superior quadrant. Alternative locations also exist including posterior-superior and posterior-inferior. The astute practitioner will refer patients for audiometric testing, which usually demonstrates a conductive hearing loss.
As previously mentioned, a large proportion of these patients will have no hearing loss early in the disease process. Such patients are fortunate, as the disease has the ability to not only destroy middle ear architecture, but to also progress to more extensive complications as well. Although rare, cholesteatoma has the ability to erode other important structures contained within the temporal bone, including the skull base itself. The list of potential complications is wide-ranging including sensorineural hearing loss, vertigo, and facial paralysis as well as intracranial complications such as brain abscesses, meningitis, and otitic hydrocephalus.
The follow-up recommendation typically involves referral to an otolaryngologist, and when the margins of the lesion are not able to be visualized, CT scan of the temporal bones without contrast is helpful to delineate the extent of disease and assess the relevant anatomy. Magnetic resonance imaging with contrast is typically reserved for those patients with suspected intracranial complications. Surgical excision is the treatment of choice and the extent of disease dictates the scope of the required procedure. Smaller cholesteatomas, which are caught early, can be excised via a transcanal approach by lifting the tympanic membrane and selectively removing the lesion from the middle ear space. Larger lesions often require more aggressive resections, which can include a postauricular incision and a mastoidectomy.
Congenital cholesteatoma is one of the more common causes of childhood onset conductive hearing loss unrelated to middle ear effusion. Undiagnosed, the disease can grow to irreversibly destroy the conductive hearing architecture, as well as the surrounding skull base of the lateral temporal bone. As most children are asymptomatic, the burden falls on primary care providers to perform pneumatic otoscopy with visualization of all quadrants of the tympanic membrane even in young children who frequently resist attempts to complete a thorough examination to rule out suspicious lesions. Despite the rarity of the disease process, the profound complications that can result from its unabated proliferation makes congenital cholesteatoma a crucial entity to be aware of during routine otologic examination so that it is detected and managed prior to the development of ossicular involvement and hearing loss.
- Centers for Disease Control and Prevention (CDC). Identifying infants with hearing loss - United States, 1999–2007. MMWR Morb Mortal Wkly Rep. 2010;59:220–223.
- Yoshinaga-Itano C, Sedey AL, Coulter DK, Mehl AL. Language of early- and later-identified children with hearing loss. Pediatrics. 1998;102:1161–1171. doi:10.1542/peds.102.5.1161 [CrossRef]
- The Commission on Education of the Deaf. Toward equality: education of the deaf. http://archive.gao.gov/t2pbat17/135760.pdf. Accessed April 1, 2016.
- Joint Committee on Infant HearingAmerican Academy of AudiologyAmerican Academy of PediatricsAmerican Speech-Language-Hearing AssociationDirectors of Speech and Hearing Programs in State Health and Welfare Agencies. Year 2000 position statement: principles and guidelines for early hearing detection and intervention programs. Pediatrics. 2000;106:798–817. doi:10.1542/peds.106.4.798 [CrossRef]
- CDC (US) 2013 EHDI Hearing Screening and Follow-up Survey (HSFS). Summary of 2013 National CDC EHDI Data. http://www.cdc.gov/ncbddd/hearingloss/2013-data/2013_ehdi_hsfs_summary_c.pdf. Accessed April 13, 2016.
- McGill TJ, Merchant S, Healy GB, Friedman EM. Congenital cholesteatoma of the middle ear in children: a clinical and histopathological report. Laryngoscope. 1991;101:606–613. doi:10.1288/00005537-199106000-00006 [CrossRef]
- Derlacki E, Clemis J. Congenital cholesteatoma of the middle ear and mastoid. Ann Otol Rhinol Laryngol. 1965;74:706–727. doi:10.1177/000348946507400313 [CrossRef]
- Tos M. A new pathogenesis of mesotympanic (congenital) cholesteatoma. Laryngoscope. 2000;110(11):1890–1897. doi:10.1097/00005537-200011000-00023 [CrossRef]
- Teed RW. Cholesteatoma verum tympani: its relationship to the epibranchial placode. Arch Otolaryngol. 1936;24:455–474. doi:10.1001/archotol.1936.00640050467004 [CrossRef]
- Levenson MJ, Michaels L, Parisier SC, Juarbe C. Congenital cholesteatomas in children: an embryologic correlation. Laryngoscope. 1988;98:949–955. doi:10.1288/00005537-198809000-00008 [CrossRef]