Canal Cholesteatoma Presentation and Management: A Systematic Review and Meta‐Analysis

Abstract

Objective

To evaluate current understanding of external auditory canal cholesteatoma (EACC), its symptomatic burden, clinical features, diagnostic approach, and management strategies to reduce delays in diagnosis.

Data Sources

PubMed, CINAHL, COCHRANE Library, and SCOPUS.

Review Methods

A comprehensive literature search was completed in March 2025. The search identified 2117 English‐language articles, of which 30 studies reported patients diagnosed with EACC. Meta‐analyses of mean difference (Δ), proportions (%), and continuous measures with 95% confidence intervals (CI) were performed using random and fixed effects models.

Results

A total of 1007 patients were included with a mean age of 43.9 years (range 6‐89). Most were diagnosed with Stage III EACC (60.7%, CI 43.5‐76.7). Nicotine use (33.1%, CI 15.2‐54.1) and cotton swab abuse (24.3%, CI 16.7‐33.7) were common risk factors. Patients most often presented with otalgia (39.9%, CI 30.5‐49.7) or otorrhea (50.3%, CI 37.8‐62.7), though 15.7% (CI 4.5‐31.6) were asymptomatic. Conservative treatment with serial debridement was used in most patients (69.6%, CI 44.5‐89.7). Canalplasty (68.6%, CI 48.3‐85.7), tympanoplasty (24.7%, CI 3.7‐56.1), and mastoidectomy (33.7%, CI 17.4‐52.3) were the most common surgical approaches. Recurrence was low (4.5%; 95% CI 2.3‐8.0).

Conclusion

Patients with EACC are frequently diagnosed at advanced stages. Recognizing risk factors and symptoms can expedite detection and guide management. This review highlights how tailored interventions achieve low recurrence rates and reduce morbidity linked to delayed diagnosis.

External auditory canal cholesteatoma (EACC) is a rare but potentially destructive otologic condition arising in 1:1000 new otologic patients. ¹ EACC is characterized by a formation of keratinizing, stratified squamous cystic lesion within the external auditory canal, unlike the more common variant found in the middle ear. These differ in both pathophysiology and location, with middle ear cholesteatoma typically arising from the tympanic membrane due to retraction pockets or chronic otitis media as opposed to EACC forming directly from the canal skin. The etiology of EACC remains unclear, although both primary idiopathic cases and secondary forms related to trauma, surgery, chronic irritation and drug use have been described. ² , ³ , ⁴

EACC typically presents insidiously, with symptoms such as otorrhea, otalgia, and hearing loss. ² Often, EACC can mimic more commonly diagnosed diseases like otitis externa, which can lead to delays in diagnosis. ² , ³ , ⁵ Additionally, it may appear similar to keratosis obturans as it shares similar characteristics of obstruction in the external auditory canal. ⁶ However, pathologically keratosis obturans is accumulation of desquamated keratin plugs, while EACC is nonmalignant invasion of squamous cell tissues with bony erosion of the ear canal. ⁷

Delay in diagnosis can result in disease progression, leading to more extensive bony erosion, chronic inflammation, and requiring more aggressive surgical intervention. ² , ⁸ Early recognition and appropriate management can reduce the risk of potential complications, including facial nerve palsy and meningitis, and limit the spread to nearby structures such as the mastoid, temporomandibular joint, and facial nerve. ⁹ To aid in diagnosis and guide treatment strategies, staging systems have been proposed that not only reflect disease severity but also assist in preoperative planning and prognosis. ¹ , ⁸ The Naim staging system, for example, has been developed based on the clinical and histologic presentation of EACC. In this system, Stage I indicates disease limited to hyperplasia of the canal epithelium without bony erosion, stage II involves limited boney erosion (periostitis), stage III describes extensive bony destruction, and stage IV is diagnosed upon erosion of adjacent structures. ¹ Management includes debridement and antibiotic ear drops for early lesions or a variety of surgical intervention including mastoidectomy and canalplasty for more severe disease and definitive care. ⁹ , ¹⁰

This review synthesizes available evidence on EACC, focusing on symptomatic burden, diagnostic challenges, and treatment strategies. By focusing on its symptomatic burden, clinical features, diagnostic challenges, and management strategies, this review highlights the need for increased awareness and early recognition to prevent misdiagnosis and improve patient outcomes.

Methods

This systematic review and meta‐analysis was completed following Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA) guidelines. ¹¹ A comprehensive literature search of Cochrane and PubMed was conducted upon inception with no systematic reviews on this topic identified. All methodological approaches and outcome measures were established before the literature search and implemented consistently throughout the review.

Identify Relevant Literature

The search strategy for this study was developed and executed by the 2 primary reviewers, AMW and MC (Supplemental Data S1, available online). A search was conducted of multiple databases including PubMed (US National Library of Medicine, National Institutes of Health), Scopus (Elsevier), and CINAHL (EBSC) from inception through March 2025. The keywords for this search were all related to EACC diagnosis. All articles included in the scope of the search for this study were uploaded into Covidence (Veritas Health Innovation Ltd.) for further screening.

Study Selection

The objective of this review was to include all published articles describing patients diagnosed with EACC. Case series, retrospective and prospective cohort studies, and cross‐sectional studies were considered for inclusion. Review articles were not included due to their inherent redundancy with quantitative data. No limit was placed on year of publication. Exclusion criteria included case reports, non‐English articles, incomplete and inaccessible articles, and study protocols. Studies solely focusing on patients previously diagnosed with congenital aural atresia were excluded due to previous systematic review on the topic.

Search Process

Included studies were initially screened for duplicates upon import into Covidence. The 2 independent screeners followed the inclusion criteria for screening of both title and abstract. The studies included during this phase of screening were further reviewed for inclusion criteria through full‐text examination by the same 2 reviewers. All conflicts were resolved through discussion, and the remaining studies were included in the data extraction phase for final analysis.

Data Charting

Data Extraction

Data extraction for this review included study author, article title, country, study design, reported demographics such as gender, age, follow‐up period, laterality of diagnosis, primary or secondary EACC, stage of diagnosis, causes of secondary EACC, presenting symptoms, risk factors, treatment modality, involved anatomic structures, bony wall involvement, and postoperative complications. Audiologic outcomes prior to and following surgical intervention were also collected when reported within study data.

Study Appraisal

Each included study was assigned a level of evidence, as described by the Oxford Center for Evidence‐Based Medicine criteria. ¹² Nonrandomized studies were individually assessed for risk of bias with the Risk of Bias in Non‐Randomized Studies–of Interventions (ROBINS‐I) assessment tool. ¹³ All case series studies were assessed for risk of bias using the Joanna Briggs Institute (JBI) Critical Appraisal Tool checklist. ¹⁴ Two independent reviewers assessed each study individual using a checklist, and all conflicting answers were reconciled through discussion between the 2 authors. Each aspect of risk of bias within the ROBINS‐I assessment was assigned a grade of low, unclear, or high. Similarly, for studies utilizing the JBI assessment, each checklist item was given a score of “1” for “yes” and “0” for “no,” or considered “not applicable,” or “unclear.” The JBI risk of bias checklist consists of 10 questions where a score of 5 or higher is considered an acceptably low risk of bias.

Definitions

Congenital categorization for secondary EACC included congenital aural atresia and branchial cleft remnants. Dural extension was separated from tegmen invasion when explicitly stated within an included study. Otalgia included any reported ear pain at diagnosis. The sensation of ear fullness was reported separately from hearing loss as a symptom. Nicotine was considered a risk factor for any patient with a documented history of smoking, regardless of the duration or amount of use. Conservative treatment included serial debridement of the EAC.

Statistical Analysis

Meta‐analysis of single means (age) and meta‐analysis of proportions (gender, patient characteristics, risk factors, and presentation) were performed by Comprehensive Meta‐Analysis (version 4; Biostat Inc.). Each measure (mean/proportion [%] and 95% confidence interval [CI]) was weighted according to the number of patients affected. The random‐effect model was chosen following a heterogeneity assessment of the outcome variables. The I ² statistic was used to quantify the proportion of variability attributable to heterogeneity rather than chance, and the Cochran's Q test (χ ²) to assess the presence of statistical heterogeneity. ¹⁵ , ¹⁶ To assess the robustness of our findings, we performed a sensitivity analysis using the one‐study removal technique, which systematically excludes 1 study at a time to evaluate the impact of individual studies on the pooled results. In addition, a comparison of proportions, expressed as difference (Δ%) and 95% CI, was done to compare outcomes between 2 groups. Finally, potential publication bias was evaluated by visual inspection of the funnel plot and Egger's test, which statistically examines the asymmetry ofthe funnel plot. ¹⁷ A P < .05 was considered to indicate a significant difference for all statistical tests.

Results

The preliminary search for this study yielded 2117 studies after removal of duplicates initially screened following inclusion criteria. There were 46 studies carried over to full text screening by 2 independent reviewers. Of the excluded studies, 8 were non‐English, 3 had incorrect outcomes, 4 included the wrong patient population, and 1 was unavailable as a full text. A total of 30 studies were remaining for final analysis (Figure 1). ¹ , ² , ³ , ⁴ , ⁸ , ⁹ , ¹⁰ , ¹⁸ , ¹⁹ , ²⁰ , ²¹ , ²² , ²³ , ²⁴ , ²⁵ , ²⁶ , ²⁷ , ²⁸ , ²⁹ , ³⁰ , ³¹ , ³² , ³³ , ³⁴ , ³⁵ , ³⁶ , ³⁷ , ³⁸ , ³⁹ , ⁴⁰

Figure 1.

Preferred reporting items for systematic reviews and meta‐analyses flow diagram of study selection.

Publication Characteristics

There were 30 studies included for analysis that were published between 1982 and 2022. These studies originated from 12 countries with 20% being completed within the United States. The majority of included papers were retrospective cohort studies (Supplemental Data S1, available online). An overall acceptable low risk of bias was indicated through critical appraisal of nonrandomized studies, with the most appreciable potential bias being due to possible confounding (Figure 2). JBI appraisal was completed for the included case series studies, indicating a low risk of publication bias and good quality with scores between 7 and 10 (Supplemental Data S2, available online). A funnel plot demonstrated little publication bias, as all studies were asymmetrically located within the funnel (Figure 3).

Figure 2.

Risk of bias following ROBINS‐I criteria. ROBINS‐I, the risk of bias in nonrandomized studies.

Figure 3.

Funnel plot demonstrating overall publication bias.

Leave‐one‐out sensitivity analyses showed that the pooled proportion of patients presenting with stage III EACC remained stable, ranging from 58.9% to 61.8% across iterations (overall 60.7%). Estimates for nicotine use (30.2%‐35.4%; overall 33.1%), cotton swab abuse (22.0%‐26.7%; overall 24.3%), otorrhea (47.5%‐52.8%; overall 50.3%), and otalgia (37.2%‐42.5%; overall 39.9%) also varied by less than 5 absolute percentage points when any single study was removed. Recurrence remained low and robust (3.6%‐5.3%; overall 4.5%), indicating that no single study unduly influenced the principal conclusions.

Patient Demographics

A total of n = 1007 patients were included within this study. The mean age of included patients was 43.9 years old (range 6‐89). There was a female predominance at 54.5% (CI 48.5‐60.4) of patients diagnosed with EACC.

EACC Attributes

Etiological Subtypes and Severity

A majority of patients (92.9%) were diagnosed with unilateral EACC (CI 89.8‐95.4) with the equal distribution between ears (Right Ear: 52.1%, CI 48.9‐55.8). Idiopathic EACC was diagnosed in 83.8% (CI 70.5‐93.6) of patients with a smaller percentage diagnosed with secondary EACC (40.0%, CI 28.4‐52.1). Secondary classifications included postoperative (37.6%, CI 20.5‐56.6), congenital (35.4%, CI 10.0‐66.5), and poststenotic (32.2%, CI 20.5‐45.2). Upon diagnosis, most patients were diagnosed with Stage III EACC (60.7%, CI 43.5‐76.7). The mean pre‐intervention air‐bone gap (ABG) for included patients was 15.6 dB (CI 5.27‐26.0).

Involved Structures and Bony Wall Involvement

The structure most commonly involved in EACC was the mastoid, as visualized on computed tomography (CT) (Table 1). A total of 63.5% (CI 60.6‐84.6) of patients had EACC affecting more than one wall of the EAC, with 18.5% (CI 9.0‐30.6) of included patients diagnosed with circumferential EACC. The bony wall most affected by EACC was the inferior (81.1%, CI 74.6‐86.8), followed by posterior (58%, CI 47.4‐68.2).

Table 1.

Structures Involved by EACC Through CT Imaging

Involved structure (CT)	n = total ears	I 2, %	Meta‐analysis of proportion (%), 95% CI
Mastoid	250	79.4	32.8 (20.1‐47.0)
TMJ	269	71.6	20.5 (11.8‐30.9)
Fallopian canal	45	0.0	8.0 (3.2‐14.7)
Lateral semicircular canal	66	0.0	5.7 (1.5‐14.1)
Tegmen	48	0.0	5.6 (1.1‐15.9)
Dura	367	70.9	2.7 (0.1‐8.9)

Abbreviations: CI, confidence interval; CT, computed tomography; EACC, external auditory canal cholesteatoma; TMJ, temporomandibular joint.

Risk Factors and Presenting Symptoms

Risk factors that occurred at the highest rate in patients developing EACC were nicotine use and cotton swab abuse. Most included patients presented with otalgia or otorrhea (Table 2, Figure 4). Approximately 15% of patients were asymptomatic upon diagnosis.

Table 2.

EACC Risk Factors and Presenting Symptoms

Variable	n = total patients	I 2, %	Meta‐analysis of proportions (%), 95% CI
Risk factor
Cotton swab abuse	105	0.0	24.3 (16.7‐33.7)
Nicotine use	242	90.0	33.1 (15.2‐54.1)
Diabetes	108	45.5	15.2 (9.2‐23.2)
Tympanoplasty	56	0.0	9.0 (3.1‐19.3)
Hearing aid use	51	0.0	11.8 (4.6‐23.4)
Steroid use	162	0.0	8.1 (4.4‐13.3)
Bisphosphonate use	245	83.3	12.4 (4.1‐24.3)
Hemodialysis	100	0.0	23.5 (15.7‐32.2)
Presenting symptom
Otorrhea	550	88.6	50.3 (37.8‐62.7)
Otalgia	541	80.5	39.9 (30.5‐49.7)
Prurigo	377	94.7	34.3 (15.3‐56.3)
Hearing loss	355	88.7	43.9 (28.6‐59.7)
Fullness	167	33.2	22.5 (14.8‐31.2)
Blockage	71	40.6	14.8 (5.9‐30.0)
Tinnitus	66	0.0	22.1 (13.1‐33.8)
Vertigo	40	0.0	16.6 (6.9‐31.2)
Facial weakness	18	0.0	14.7 (3.1‐37.5)
Asymptomatic	126	70.9	15.7 (4.6‐31.6)

Abbreviations: CI, confidence interval; EACC, external auditory canal cholesteatoma.

Figure 4.

Forest plot demonstrating publication bias for Otorrhea.

Treatment and Outcomes

Conservative treatment, including serial debridement, was utilized for most patients with EACC (69.6%, CI 44.5‐89.7). Of those requiring surgical intervention, the majority of patients underwent a canalplasty (68.6%, CI 48.3‐85.7) followed by tympanoplasty (24.7%, CI 3.7‐56.1) as a surgical option for EACC treatment. Mastoidectomy was performed in 33.7% (CI 17.4‐52.3) of patients with canal wall down mastoidectomy occurring in 31.6% (CI 13.4‐53.5). The rate of recurrence of EACC was 4.5% (CI 2.3‐8.0) and the rate of reperforation was 8.2% (CI 4.1‐14.2) within our study population.

Discussion

This meta‐analysis provides an examination of the clinical presentation, radiologic features, and management of EACC, a rare otologic disease present in our large study cohort (n = 1007). Diagnosis of this disease presented at a late‐stage in the majority of our patient population (Stage III = 60.7%). Predominant risk factors included smoking and cotton swab use with a large subset undergoing debridement or canalplasty. Recurrence rates were largely low across our study cohort (4.5%). These important findings reinforce the need for providers to recognize the presentation and risk factors for early diagnosis. Although our analysis is constrained by study‐level rather than patient‐level data, leave‐one‐out sensitivity analyses suggest that the main findings regarding stage at presentation, risk factor profile, and low recurrence rates are robust to exclusion of any single study.

External auditory canal cholesteatoma is predominantly unilateral in adult populations, with bilateral cases being rare. ³ , ⁸ This finding was replicated in this study with unilateral disease affecting over 90% of our study population, which is typical of primary EACC and disease secondary to local factors (surgery, trauma, chronic inflammation, etc.). However rare, bilateral disease, consequently, should prompt consideration of underlying systemic, congenital, or syndromic conditions, such as congenital aural atresia or stenosis, or rare systemic diseases (eg, Langerhans cell histiocytosis). ³ , ⁴¹ A finding of bilateral disease might also lend to a diagnosis of Keratosis Obliterans, a keratinizing lesion sometimes mistaken for EACC. ²³

Risk factors for EACC were wide‐spread within this review, with the most common causes associated with nicotine use (33.1%) and external trauma to the ear (24.3%). The detrimental vascular effects of smoking are well‐known, with microangiopathy and diminished microcirculation in the external auditory canal may be contributing to an increased likelihood of EACC in this patient population. ³ , ²⁶ Microvascular compromise due to nicotine is believed to predispose canal epithelium to chronic inflammation, impaired epithelial migration, and subsequent keratin accumulation, which are imperative to the pathogenesis of EACC. ³ , ²⁶ External canal trauma, inclusive of direct injury (blunt trauma, laceration), ⁴² , ⁴³ iatrogenic trauma (surgical intervention, repeated instrumentation), ³⁸ , ⁴⁴ and repetitive micro trauma (ear cleaning methods, hearing aid use), ⁴⁵ has been shown to be related to higher rates of developing EACC. This is proposed to be due to disruption of the integrity and focal devitalization of the canal wall, leading to accumulation of keratin and formation of canal cholesteatoma. ⁴⁴

Clinical presentation of EACC most commonly included otorrhea (50%) and hearing loss (44%), though there was not one symptom that was experienced by the vast majority of patients. Infection of the retained keratin debris with chronic inflammation can lead to consistent drainage of the ear. ⁴⁶ Conductive hearing loss can develop in these patients when the expanding cholesteatoma mass obstructs the canal or, in advanced stages, invades the tympanic membrane or ossicles. Interestingly, otalgia is a less common symptom in patients with EACC, likely due to its insidious and slow development associated with early lesions solely limited to the bony canal. Without extension into the periosteum, it is possible patients may not feel any pain until the disease process advances or becomes further complicated. ² , ³ Appropriate clinical suspicion for EACC should exist for patients with a history of smoking and repetitive ear cleaning habits presenting with otorrhea and subjective hearing loss. Asymptomatic presentation is not uncommon, with 15% of our patient population exhibiting no outward symptoms at the time of diagnosis underscoring the importance of maintaining a high index of suspicion even in the absence of clear symptoms.

Naim staging is the most widely used classification system for EACC, focusing on clinical and histopathological findings. ¹ While radiographic imaging like CT can aid in surgical planning, it is not required for staging. ² , ²⁵ Stage I and II reflect hyperplasia of the canal epithelium and periostitis of the EAC, respectively. Bony canal defects distinguish stage II from stage III, highlighting bone erosion as an indicator of advancing disease. Stage IV indicates extension beyond the EAC into surrounding structures, such as the mastoid, middle ear, or TMJ. Within our study, most patients were diagnosed at stage III (60.7%), emphasizing the importance of early disease detection. The timing of this diagnosis is potentially hindered by the asymptomatic or minimally symptomatic nature of early disease. This distribution may also be influenced by publication bias, as more advanced or surgically managed cases of EACC are more likely to be reported in the literature. Upon advancement and extension of disease, the mastoid was the most commonly involved structure outside of the EAC (32%), particularly likely to occur in posterior wall lesions (58%) due to anatomic proximity. TMJ involvement was also reported frequently (20%), typically associated with an inferiorly located EACC (81%). Therefore, recognition of expansion patterns may be valuable in predicting potential complications and guiding appropriate management

Conservative management, including regular aural debridement and close follow up, is typically utilized for early‐stage disease and can be a first‐line treatment option for cases that have not invaded the bony canal. This treatment option, the most commonly reported in our study (69%), has the capacity to be completed in‐office, thereby reducing surgical complications and saving healthcare costs. For cases of more extensive disease, persistent symptoms, or failure of serial debridement, surgical intervention may be necessary. The choice of procedure type is guided by extent of bony disease and involvement of adjacent structures. Canalplasty was the most common surgical option (68%) within our patient population, which is performed to widen the canal, facilitate removal of disease, and restore the self‐cleaning function of the canal typically for stage II or III EACC. ⁴ , ³⁵ Mastoidectomy is utilized upon mastoid air cell extension and can be combined with canalplasty. It may be unknown whether there is mastoid extension present with high‐resolution CT imaging pre‐operatively, and clinical judgement of advanced disease may be necessary to decide on addition of this procedure. ³⁹ An adjunct procedure to canalplasty and mastoidectomy, typically occurring when disease extends into the tympanic membrane or middle ear structures, is tympanoplasty, occurring in 24% of included patients. Though surgical success rates were outside the scope of this study, recurrence and reperforation rates were low across the patient cohort.

Limitations

This analysis is subject to several limitations, some of which are inherent to the methodology of review articles. Grey literature was not included which may limit the capture of unpublished data. This approach, however, was chosen to ensure inclusion of studies with adequate methodological detail and outcome reporting to minimize variable reporting quality and risk of bias. As this study relies on the data reporting of published articles, patient‐level information is not accessible for use. This limits the ability to subgroup data and perform further analysis on risk analysis. More specifically, we are unable to examine what specific surgical procedures led to reperforation of the tympanic membrane, recurrence of disease, or the postoperative diagnosis of meatal stenosis. The surgical procedure sub‐grouped by stage of disease was also unable to be extracted due to limitations in patient‐specific data. Although leave‐one‐out sensitivity analyses suggested that the principal pooled estimates for stage at presentation, major risk factors, and recurrence were robust to exclusion of individual studies, these methods cannot compensate for unmeasured confounding, inconsistent reporting, or selective publication, and residual bias is likely to persist.

Conclusion

This study calls attention to the key risk factors and common presentation of EACC, reviewing available treatment approaches. At diagnosis, a majority of cases were at an advanced stage, emphasizing the need for provider recognition of this rare disease. Clinical identification of EACC severity, with potential utilization of radiographic imaging, is crucial to examine the extension of disease for both deciding upon management options and providing prognosis information. Early recognition and timely intervention are essential to improving patient outcomes and minimizing complications associated with extensive disease progression in EACC.

Author Contributions

Angelica M. Walker: conceptualization; investigation; formal analysis; writing—original draft; writing— review and editing; visualization; Matthew Cheung: conceptualization; formal analysis; investigation; writing—original draft; writing—review and editing; Shaun A. Nguyen: formal analysis; writing—review and editing; Kate Bonham: formal analysis; investigation; writing—review and editing; Erin A. Harvey: conceptualization; writing—review and editing; visualization; Robert F. Labadie: conceptualization; writing—review and editing; visualization; Ted A. Meyer: conceptualization; writing—review and editing; visualization.

Disclosures

Competing interests

None.

Funding source

None.

Supporting information

Supplemental Data ‐ Canal Cholesteatoma.