A Comparison of Patterns of Disease Extension in Keratosis Obturans and External Auditory Canal Cholesteatoma

External Ear Disease: Keratinaceous Lesions of the External Auditory Canal

Keratosis obturans (KO) and external auditory canal cholesteatoma (EACC) are two distinct keratinaceous lesions of the external ear. This article reviews the signs, symptoms, pathophysiology, workup, and treatment of each. Patients with either pathology can often be managed in the clinic with debridement; however, EACC is more likely to involve osteonecrosis and require more extensive operative management if disease is not confined to the canal on account of the bony erosion characteristic of cholesteatoma. If required for extensive disease, surgical approaches to both pathologies are similar.

Modified-modified radical mastoidectomy

PURPOSE

It is unusual to have communication from the external auditory canal (EAC) directly to the mastoid, totally sparing the tympanum. These patients need a different surgical approach, a modified canal wall-down procedure, to completely clear the disease but fully preserve the tympanum. We present one such exceptional case.

CASE PRESENTATION

A 28-year-old lady presented with ear discharge for 1 year. Imaging confirmed the canal-mastoid fistula, but the entire tympanum was normal. We performed a modified-modified radical mastoidectomy.

CONCLUSIONS

Canal-mastoid fistula is an infrequent entity and may be idiopathic. Despite being evident on clinical examination, imaging aids in assessing size and location of the defect. Although EAC reconstruction may be attempted, the majority require a canal wall-down procedure.

Taste Alteration in External Auditory Canal Cholesteatoma: Indicator of Impending N VII Affection

INTRODUCTION

External auditory canal cholesteatoma (EACC) is a rare disease, with an estimated incidence of approximately 1:1,000 adult and 1.6:1,000 pediatric otologic patients. Systematic studies of chronic ear disease and taste alteration prior to surgery are rare; in fact, there are no such studies for EACCs. Therefore, we describe chorda tympani nerve (CTN) dysfunction and the related clinical consequences in EACC patients.

METHODS/STUDY DESIGN

Between 1992 and 2021, we retrospectively analyzed the symptoms, signs, and radiological and intraoperative descriptions of CTN involvement in 73 patients. Liquid taste tests and, since 2009, Taste StripsTM as well as an olfactory screening test (Smell DiskettesTM) have been performed for all symptomatic patients and, when feasible, all other EACC patients.

LEVEL OF EVIDENCE: 4

RESULTS

Ten of 73 patients complained subjectively of dysfunction, and 8 showed abnormal taste test results. Four patients complained of olfactory dysfunction (3 cases with pathological taste tests). Gustatory dysfunction was most frequent in radiogenic EACC cases (n = 4), followed by postoperative EACC (n = 3). Two postoperative patients were asymptomatic despite abnormal test results. Rarely, patients with idiopathic (n = 2) and posttraumatic (n = 1) EACC showed acute taste dysfunction that was confirmed in each with abnormal test results.

DISCUSSION/CONCLUSION

CTN dysfunction often developed asymptomatically in chronic ears, except for idiopathic and posttraumatic EACCs under previous healthy middle ear conditions. Taste disturbance is not a cardinal symptom of EACC, but objective testing suggests that up to one out of 10 EACC patients with advanced disease may experience regional gustatory dysfunction prior to surgery. Especially in context of a new and acute presentation, regional taste dysfunction may alert the clinician of potential progressive EACC invasion and danger to the facial nerve.

Imaging the External Ear: Practical Approach to Normal and Pathologic Conditions

The external ear (EE) is an osseous-cartilaginous structure that extends from the auricle to the tympanic membrane. It is divided into two parts: the auricle (or pinna) and the external auditory canal (EAC). Given the ease of access to the EE, imaging studies are not always needed to make a diagnosis. However, when lesions block visual access to areas deep to the EE abnormality, complications are suspected, or there is lack of response to treatment, imaging becomes essential. A basic understanding of the embryologic development and knowledge of the anatomy of the auricle and EAC are useful for accurate diagnosis of EE lesions. Congenital, traumatic, inflammatory, neoplastic, and vascular conditions can affect the EE. An overview of the anatomy and embryologic development of the EE is presented, with discussion and illustrations of common and uncommon conditions that affect EE structures and a focus on the CT and MRI features that are of interest to radiologists. CT is usually the first diagnostic modality used to evaluate the EAC and is the superior method for demonstrating bone changes. MRI provides excellent tissue characterization and enables one to better define lesion extension and perineural tumor spread. In addition, a flowchart to facilitate the differential diagnosis of EE abnormalities is provided. Online supplemental material is available for this article. ^©RSNA, 2022.

Keratosis obturans: A rare cause of facial nerve palsy

Keratosis obturans, caused by the deposition of desquamated keratin plug in the external auditory canal can present with facial palsy. Young patients presenting with facial palsy, earache, and gradual hearing loss should be suspected for Keratosis obturans.

Contemporary management of keratosis obturans: a systematic review

OBJECTIVE

This study aimed to examine the medical literature regarding the natural history and management of keratosis obturans.

METHOD

PubMed was queried via the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol, and the methodological quality of each study was assessed using the Methodological Index for Non-Randomized Studies criteria.

RESULTS

Fifty-one studies were abstracted, and dual investigator screening resulted in five retrospective studies for final analysis. All studies included patients afflicted with either unilateral (n = 75) or bilateral keratosis obturans (n = 8). The definition of keratosis obturans was present in three studies: a desquamated keratin plug within the external auditory canal. Mean and median Methodological Index for Non-Randomized Studies scores were 9.5 and 9.5, respectively. All patients underwent keratosis obturans exenteration with microscopy. Two studies reported an outcome instrument to evaluate endpoints: marked stillette and audiometry. No complications were observed with follow-up periods from 3 weeks to 3.5 years.

CONCLUSION

This comprehensive review highlights a lack of published evidence relating to keratosis obturans. However, it appears keratosis obturans treatment is safe and efficacious with identifiable clinical practice patterns.

Primary external auditory canal cholesteatoma of 301 ears: a single-center study

PURPOSE

Limited literature exists on primary external auditory canal (EAC) cholesteatoma (EACC). Here, we focus on the clinical features of this rare disease, especially the invasive patterns of lesion progression, through a large population study and present simple and practical staging.

METHODS

In all, 276 patients (male 99; female 177; mean age 41.3 ± 21 years; ears 301) with primary EACC were retrospectively analyzed. Stage I indicated EACC without bony lesions, stage II indicated invasion confined within EAC, stage III indicated invasion beyond the EAC involving mastoid air cells or tympanic cavity, but within the temporal bone, and stage IV indicated invasion beyond the temporal bone.

RESULTS

In all, 41, 219, 40, and 1 ear with Stage I, II, III, and IV lesions were found, respectively. Common clinical symptoms were hearing loss (237 ears, 78.7%), otalgia (221 ears, 73.4%), and otorrhea (85 ears, 28.2%). The mean air conduction and air-bone gaps were 45.4 ± 17.9 dB HL and 24.6 ± 15 dB HL, respectively. EACCs were found to invade in all directions of the EAC, with the inferior wall (224 ears, 74.4%) > posterior wall (207 ears, 68.8%) > anterior wall (186 ears, 61.8%) > superior wall (86 ears, 28.6%) invasion; multiwall invasions (207 ears) were common; however, inward invasions into the tympanic cavity were rare.

CONCLUSION

Primary EACCs occurred mostly in women and often unilaterally invaded multiple bony walls in the lower half of the EAC. The present staging reflects the patterns and severity of lesion progression and may be beneficial in treatment planning.

A Wolf in Sheep's Clothing: Keratosis Obturans Causing Facial Nerve Palsy - A Case Report with Review of the Literature

Keratosis obturans is a benign disease caused by layered impaction of wax within the external auditory canal. It presents with acute onset of pain and ear blockade. The current report discusses a 24-year-old male patient with recurrent unilateral keratosis obturans associated with facial canal erosion and resulting in facial palsy. A detailed review of the literature is presented. Keratosis obturans can behave aggressively, resulting in significant erosion of the bone and intratemporal structural damage and complications. Timely intervention is vital.

Clinical analysis of pediatric primary external auditory canal cholesteatoma

OBJECTIVE

Pediatric primary external auditory canal cholesteatoma (EACC) is a rare disease. The present study aimed to explore the clinical features and prognosis of this disease.

METHODS

Clinical data of 41 ears with pediatric primary EACC were collected, and the clinical characteristics and prognosis were analyzed in this retrospective study.

RESULTS

A total of 35 patients (median age of 13 years) were recruited in this study. Of these, 13 suffered on the left side and 16 on the other side, while 6 suffered on the bilateral ears. A total of 35 ears had hearing loss, 26 had otalgia, 15 had otorrhea, 12 had tinnitus, and 4 had pruritus. The median course of the disease was 1 month. The bone destruction of the external auditory canal (EAC) was located on the inferior wall of 20 ears, the posterior wall of 22 ears, the superior wall of 15 ears, and the anterior wall of 15 ears. According to Shin's stages, 24 ears were in stage I, 2 in stage II, 15 in stage III. A total of 40 ears underwent transcanal cholesteatoma removal (TCR) and 1 underwent both TCR and tympanoplasty. Finally, 33 ears were followed up postoperatively, and only 1 ear presented recurrence.

CONCLUSION

The posterior wall of the EAC is the most commonly affected wall, and the involvement of multiple walls is common. Due to the remodeling of the EAC bone in pediatric patients, the high stage lesions can be treated by minimally invasive surgical debridement combined with a close follow-up postoperatively.

Keratosis Obturans: A Disease of the Tropics?

Keratosis obturans appears to be an obscure and relatively uncommon entity, even in literature search of journals and reference texts, so much so that there is not even any prevalence or incidence statistics available. However, the condition did not appear to be as uncommon based on our clinical observations. We have managed to obtain 64 patients representing 67 ears with keratosis obturans in our study period of about 18 months with a pattern of occurrence during this period. Humid weather seemed to play a role in the frequency of its appearance during certain period in our observation. There also appears to be a correlation between the severity of symptoms (predominantly pain and hearing loss) and the presenting appearance of the condition, i.e., presence or absence of granulation tissue, as well as that the degree of difficulty in exenteration of the keratosis obturans (matrix and content) depending on the expansion of the bony canal. Our figures showed the majority of the patients are females and young individuals, the majority of them occur unilaterally. The condition also appear to stop short of involving the tympanic membrane with only the bony canal being expanded with the surrounding oedema creating an apparent "canal stenosis".

Expression of Apoptotic vs Antiapoptotic Proteins in Middle Ear Cholesteatoma

Objectives

To explore the role of antiapoptotic and apoptotic processes in the development of cholesteatoma by investigating the expression of an antiapoptotic (c-FLIP) and apoptotic (p53) protein relative to the expression of a proliferation marker (Ki-67).

Study Design

Basic science study.

Setting

Tertiary referral center.

Subjects and Methods

An immunohistochemical investigation was performed on 35 cholesteatoma specimens (21 acquired, 14 congenital) and 10 normal retroauricular skins to evaluate the expression of c-FLIP, p53, and Ki-67. The expression rate of each marker was measured to assess the difference between retroauricular skin and cholesteatoma, as well as between congenital and acquired cholesteatoma.

Results

c-FLIP expression was significantly higher in the cholesteatoma specimens than in retroauricular skin ( P < .05), while the expression of p53 did not significantly differ between the two. Ki-67 expression in cholesteatoma was significantly higher than in retroauricular skin ( P < .001). The c-FLIP expression rate was positively correlated with that of Ki-67 ( r = 0.47, P = .001), and there was no significant correlation between the expression level of p53 and that of Ki-67 ( r = 0.152, P = .319). In addition, no differences in c-FLIP, p53, and Ki-67 expression rates were evident between congenital and acquired cholesteatoma.

Conclusions

The upregulation of c-FLIP together with unchanged p53 suggests an altered equilibrium between apoptosis and antiapoptosis, favoring antiapoptosis, and may play a role in the pathogenesis of cholesteatoma.

Clinical Characteristics of Keratosis Obturans and External Auditory Canal Cholesteatoma

Objective

Keratosis obturans (KO) and external auditory canal cholesteatoma (EACC) have been considered separate entities. While the disorders are distinct, they share many overlapping characteristics, making a correct diagnosis difficult. In the present study, we compared their clinical characteristics and radiological features to clarify the diagnostic criteria.

Study Design

Retrospective case series.

Setting

Academic medical center.

Subjects and Methods

The clinical data of 23 cases of EACC and KO were retrospectively reviewed. The following clinical characteristics were compared between the 2 groups: sex, age, onset of symptoms, follow-up period, audiometric results, and imaging findings on temporal bone computed tomography including bilaterality, location, and the presence of extension to adjacent tissue.

Results

The mean age of the EACC group was significantly older than that of the KO group. All of the cases of EACC occurred unilaterally, and bilateral occurrences of KO were observed in 4 of 9 cases. All of the lesions in the KO group were circumferential, and no lesion in the EACC group invaded the superior canal wall. No significant differences in symptoms, such as acute otalgia, otorrhea, and hearing loss, were noted between the 2 groups. The incidence of conductive hearing impairment more than 10 dB was higher in the KO group than in the EACC group.

Conclusion

Thus, KO and EACC are 2 distinct disease entities that share common features in clinical characteristics except for predominant age and bilaterality. Conservative treatment with meticulous cleaning of the lesion was successful in most cases with a long-term follow-up.