Histologic description of acquired cholesteatomas: comparison between children and adults

PANEL 3: Otitis media animal models, cell culture, tissue regeneration & pathophysiology

OBJECTIVE

To review and summarize recently published key articles on the topics of animal models, cell culture studies, tissue biomedical engineering and regeneration, and new models in relation to otitis media (OM).

DATA SOURCE

Electronic databases: PubMed, National Library of Medicine, Ovid Medline.

REVIEW METHODS

Key topics were assigned to the panel participants for identification and detailed evaluation. The PubMed reviews were focused on the period from June 2019 to June 2023, in any of the objective subject(s) or keywords listed above, noting the relevant references relating to these advances with a global overview and noting areas of recommendation(s). The final manuscript was prepared with input from all panel members.

CONCLUSIONS

In conclusion, ex vivo and in vivo OM research models have seen great advancements in the past 4 years. From the usage of novel genetic and molecular tools to the refinement of in vivo inducible and spontaneous mouse models, to the introduction of a wide array of reliable middle ear epithelium (MEE) cell culture systems, the next five years are likely to experience exponential growth in OM pathophysiology discoveries. Moreover, advances in these systems will predictably facilitate rapid means for novel molecular therapeutic studies.

Recurrence in cholesteatoma surgery: what have we learnt and where are we going? A narrative review

Treatment of cholesteatoma is surgical and has historically encompassed two main techniques: canal wall up (CWU) and canal wall down (CWD) tympanoplasty. Follow-up for cholesteatoma is still debated and can be either radiological or with second-look surgery. MRI with diffusion weighted sequences has proved to have high sensitivity and specificity in detecting recurrent or residual disease. Specifically, non-echo planar imaging DWI (non-EPI DWI) has been shown to be superior to other imaging techniques, allowing, in some cases, to avoid second-look surgery. Both residual and recurrence rates are higher in CWU compared to CWD procedures. Endoscopic ear surgery (EES) has become popular with the advantage of “looking around corners”. The endoscope is used in addition to a microscope or exclusively to reduce cholesteatoma recurrence. In addition, it has been demonstrated that mastoid obliteration and the use of potassium titanyl phosphate laser (KTP) can reduce cholesteatoma recurrence, with better functional outcomes. A synthetic sulphur compound (MESNA) may have an interesting role in the overall improvement in recurrence and residual cholesteatoma disease. This narrative review critically appraises the factors associated with the risk of recurrent cholesteatoma.

Radiological and audiological predictors of stapes destruction in adherent pars tensa

PURPOSE

Progressive adherent pars tensa occasionally induces ossicular erosion. Specifically, stapes discontinuity adversely affects postoperative hearing. However, this irretrievable sequela is challenging to prove preoperatively, partly because perimatrix inflammation on the pars tensa can obscure the visibility of the ossicles or the partial volume effect of computed tomography (CT) imaging can hamper detailed ossicular visualization. Therefore, there is no consensus regarding the ideal timing for switching from a wait-and-see approach to a surgical one. Herein, we aimed to explore the potential predictors of stapes superstructure destruction in adherent pars tensa.

METHODS

This retrospective cohort study enrolled consecutive patients who underwent primary tympanoplasty for adherent pars tensa categorized as grade IV on Sadé's grading scale between April 2016 and September 2021. The impact of features on otoscopy and CT and air-bone gap (ABG) on stapes superstructure destruction was assessed using uni- and multivariable logistic regression analyses.

RESULTS

Sixty-four ears were included. Multivariate analysis revealed the presence of debris on the adherent pars tensa (odds ratio [OR] [95% confidence interval {CI}]): 4.799 [1.063-21.668], p = 0.0415), presence of soft-tissue density occupying the oval window (OR [95% CI]: 13.876 [3.084-62.437], p = 0.0006), and a ≥ 20-dB preoperative ABG at 3 kHz (OR [95% CI]: 7.595 [1.596-36.132], p = 0.0108) as independent predictors for stapes superstructure destruction.

CONCLUSION

High preoperative awareness of the possibility of destruction of the stapes superstructure would enable the surgeon to make a timely decision to provide surgical intervention before progression to severe stapes destruction, thereby maintaining long-term satisfactory hearing.

A Role for Mast Cell-Mediated Antibodies in the Formation of Cholesteatoma and Cholesteatoma-Induced Bone Erosion

The study aimed to evaluate the effects and relationships between mast cells in the matrix, mast cell enzymes tryptase and chymase, epithelial proliferation, microvascular density, and bone destruction in cholesteatoma. Thirty-five biopsies diagnosed with cholesteatoma and seven healthy skin tissues taken from the retro-auricular region for control were evaluated. Immunohistochemical studies were performed with CD117, CD34, Ki-67, chymase, and tryptase antibodies, in a single session for all cases and the control group. The relationship between erosion size and antibody load was determined. The mean cholesteatoma epithelium Ki-67 was higher than the control group (p < 0.001). CD117-positive mast cells, chymase-positive mast cells, tryptase-positive mast cells, and microvessel density were significantly higher in the cholesteatoma matrix compared to the control group (p < 0.002, p < 0.001, p < 0.005). In the group with bone erosion scores of two and above, immunohistochemical markers tended to be higher. A positive correlation was found between CD117 and chymase, tryptase, and microvessel density; between tryptase, chymase, and microvessel density; and between chymase and microvessel density. CD117-positive mast cells and chymase-positive mast cells stimulate angiogenesis, increase the epithelium's proliferative capacity in the cholesteatoma matrix, and form cholesteatoma. The increased proliferation of cholesteatoma epithelium and increased vascular density in the matrix exacerbate bone erosion.

The Relationship between the M1/M2 Macrophage Polarization and the Degree of Ossicular Erosion in Human Acquired Cholesteatoma: An Immunohistochemical Study

The differential involvement of the macrophage activation phenotypes (M1 vs. M2) has been linked to disease severity in various chronic inflammatory disorders. Pharmacologic manipulation of the M1/M2 macrophage polarization has shown therapeutic potential. Cholesteatoma is a destructive chronic middle ear disease with potentially life-threatening complications. The distribution of macrophage polarization phenotypes in middle ear cholesteatoma has not been described. In the present study, human cholesteatoma specimens acquired during tympanomastoidectomy were retrospectively retrieved and immunohistochemically characterized using a combination of antibodies labeling M1 macrophages (CD80), M2 macrophages (CD163), and total macrophages (CD68). The correlations between the immunohistochemical findings and clinical presentation were assessed. The findings revealed that cholesteatomas with more extensive ossicular erosion demonstrated a significantly higher number of M1 (CD80+) cells and a higher M1/M2 ratio than less invasive cholesteatomas (Wilcoxon test, p < 0.05). The extent of ossicular erosion correlated significantly with the M1/M2 ratio (Spearman correlation coefficient ρ = 0.4, p < 0.05). Thus, the degree of ossicular erosion in human acquired cholesteatoma appears to be related to the M1/M2 macrophage polarization. The investigation of macrophage polarization and functions in various clinical presentations of middle ear cholesteatoma is of great interest since it may contribute to the development of pharmaceutical treatment approaches.

Renal Pelvic Cholesteatoma: An Uncommon Finding in Children

Renal cholesteatoma or keratinizing desquamative squamous metaplasia is infrequent in adults and rare in children. We report a case of renal cholesteatoma in a 4-year-old male child who was referred to us as a case of multiple renal calculi with hydronephrosis. We also discuss his management with a review of relevant literature.

Extensive qPCR analysis reveals altered gene expression in middle ear mucosa from cholesteatoma patients

The middle ear is a small and hard to reach compartment, limiting the amount of tissue that can be extracted and the possibilities for studying the molecular mechanisms behind diseases like cholesteatoma. In this paper 14 reference gene candidates were evaluated in the middle ear mucosa of cholesteatoma patients and two different control tissues. ACTB and GAPDH were shown to be the optimal genes for the normalisation of target gene expression when investigating middle ear mucosa in multiplex qPCR analysis. Validation of reference genes using c-MYC expression confirmed the suitability of ACTB and GAPDH as reference genes and showed an upregulation of c-MYC in middle ear mucosa during cholesteatoma. The occurrence of participants of the innate immunity, TLR2 and TLR4, were analysed in order to compare healthy middle ear mucosa to cholesteatoma. Analysis of TLR2 and TLR4 showed variable results depending on control tissue used, highlighting the importance of selecting relevant control tissue when investigating causes for disease. It is our belief that a consensus regarding reference genes and control tissue will contribute to the comparability and reproducibility of studies within the field.

Analysis of Inflammatory Signaling in Human Middle Ear Cell Culture Models of Pediatric Otitis Media

OBJECTIVES/HYPOTHESIS

Cell culture models are valuable tools for investigation of the molecular pathogenesis of diseases including otitis media (OM). Previous study indicates that age-, sex-, and race-associated differences in molecular signaling may impact disease pathophysiology. Currently, a singular immortalized middle ear epithelial (MEE) cell line exists, HMEEC-1, derived from an adult without known middle ear disease. In this study, HMEEC-1 and primary MEE cultures from pediatric patients with and without OM were stimulated with inflammatory cytokines or OM-pathogenic bacterial lysates to examine differences in the response of molecules associated with OM pathogenesis.

STUDY DESIGN

Case-control series.

METHODS

MEE cultures were established from patients aged <6 years: two with recurrent OM (ROM), two with OM with effusion (OME), and one patient without OM who was undergoing cochlear implant surgery control undergoing cochlear implantation (Peds CI). Primary MEE cultures and HMEEC-1 cells were stimulated with tumor necrosis factor-α, interleukin (IL)-1β, or nontypeable Haemophilus influenzae lysate. TNFA, IL1B, IL6, IL8, IL10, and MUC5B were assayed via quantitative polymerase chain reaction. IL-8 was assayed by enzyme-linked immunosorbent assay.

RESULTS

Gene/protein target expressions were frequently higher in pediatric OM lines than in HMEEC-1 and Peds CI. HMEEC-1 cells were frequently less responsive to stimuli than all pediatric lines. OME lines were often more responsive than ROM lines.

CONCLUSIONS

OM may be associated with specific molecular phenotypes that are retained in primary cell culture. Adult-derived HMEEC-1 cells differ significantly in baseline expression and response of OM-associated molecules relative to pediatric MEE cells. Work is underway to immortalize pediatric OM MEE cultures as improved tools for the OM research community.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:410-416, 2021.

HRCT imaging of acquired cholesteatoma: a pictorial review

Chronically discharging ear is a common cause of morbidity in developing countries, and it is also associated with intratemporal and intracranial complications. The surgeon is often able to detect the disease. However, cholesteatoma in the "hidden areas" like anterior epitympanic recess and sinus tympani can be missed. Facial nerve involvement and cholesteatomatous erosion of the bony labyrinth are dreaded complications, the extent of which cannot be assessed completely on clinical examination. Adding to the complexity are the various variations in anatomy like high riding jugular bulb and aberrant internal carotid artery which could lead to catastrophic complications during surgery if left undetected preoperatively. HRCT temporal bone is useful to detect the extent of the disease, various complications, and guide the surgeon for pre-operative planning. In this review, we go through the various HRCT imaging features of acquired cholesteatoma, a reporting template, and a few words about imaging of the post-operative ear.

Analysis of KRT1, KRT10, KRT19, TP53 and MMP9 expression in pediatric and adult cholesteatoma

Cholesteatoma is an epidermal cyst with still unknown pathomechanism. The aim of the current study was to investigate molecular differences in the background of the hyperproliferative property and aggressive behavior typical of the cholesteatoma epithelium. The expression of three cytokeratin genes (KRT1, KRT10 and KRT19), the matrix metalloproteinase 9 gene (MMP9) and the tumor suppressor TP53 gene was measured by qRT-PCR in surgical samples of pediatric and adult cholesteatoma cases and their expression level was compared to that of normal skin samples from the retroauricular region of control individuals. Cholesteatoma samples were stratified according to the age of onset and recurrence for more detailed analysis. Our results showed identical expression pattern for KRT1 and KRT10, their expression was higher in pediatric cases than in adults, especially in pediatric recurrent samples. The expression level of KRT19 was inversely proportional to that of KRT1/KRT10, it was lower in the more invasive recurrent cases both in our pediatric and adult groups. As it was expected from the bone destructive behavior of cholesteatoma, a significantly elevated expression of MMP9 was measured in cholesteatoma samples, the highest level was found in adult recurrent cases. Low expression levels characterize the TP53 gene without significant differences in our samples. These findings demonstrate that cytokeratin expression distinguishes between pediatric/adult, nonrecurrent/recurrent cases, suggesting that distinct differentiation state and cell division potential characterize these cholesteatoma cases. KRT19 with a tumor suppressor potential might restrict the recurrence of cholesteatoma. The differences observed in gene expression profiles between cholesteatoma and control samples support the notion that cholesteatoma is a cystic lesion with tumor-like behavior because it is characterized by invasive, destructive growth and high tendency for recurrence.

Pathogenesis and Bone Resorption in Acquired Cholesteatoma: Current Knowledge and Future Prospectives

Cholesteatoma is a cystic non tumorous lesion of the temporal bone that has the ability to destroy nearby structures by its power to cause bone resorption and as a result, fatal complications prevail. We aimed to conduct a comprehensive review for pathogenesis of acquired cholesteatoma, bone resorption mechanisms, and offer a future vision of this serious disease. We have reviewed different theories for pathogenesis of acquired cholesteatoma including the most relevant and updated ones with special emphasis on the mechanisms of bone resorption through Medline/PubMed research using the keywords 'aetiopathogenesis, bone resorption, acquired cholesteatoma, temporal bone, and cytokines.' In order to strengthen our study, we searched the reference lists of identified reviews. Cholesteatoma is a subject of debate among otolaryngologists since it was prescribed firstly. Over many decades, several theories were postulated for aetiopathogenesis of cholesteatoma with a tendency to follow more than one theory to explain the proper nature of that disease. Until now, the mechanism of bone resorption has yet to be more clarified. In the last century, a leap has occurred in the field of biomolecular cholesteatoma research which improved our knowledge about its pathophysiology and bone destructive mechanism. However, surgery is still the only available treatment. We conclude that discovery of new therapeutic choices for cholesteatoma other than surgery by the use of anti-growth, anti-proliferative, apoptotic agents as well as medications that antagonize osteoclastogenesis should be the main concern in the future clinical and experimental research work. Also, searching for predictors of the aggressiveness of cholesteatoma can affect the timing of intervention and prevent occurrence of complications.

Assessment of Subepithelial Angiogenesis in Acquired Cholesteatoma between Pediatric and Adult Patients

Objective

The aim of this study was to compare subepithelial angiogenesis developing within the perimatrix of the cholesteatoma between pediatric and adult patients.

Methods

Sixty-one patients who underwent mastoidectomy for the first intent because of chronic otitis media with cholesteatoma between 1993 and 2013 and from whom appropriate tissue specimens were taken were included in the study. The patients were classified in the pediatric patient group if they were under the age of 18 years and the adult patient group if they were 18 years and older. Immunohistochemical staining for CD-31 was performed on new sections taken during surgery and sections prepared from archived tissues in paraffin blocks. Results were compared between the groups.

Results

A total of 61 patients, of whom 25 were pediatric and 36 were adult patients, were included in the study. The mean CD-31 immunopositive microvessel rates were 8.8 (3-15) and 6.61 (2-14) for the pediatric and adult patient groups, respectively. The difference between the groups was statistically significant (p=0.037). Correlation analysis showed a statistically significant negative correlation between the CD-31 immunopositive microvessel rates and age (p=0.036).

Conclusion

Subepithelial angiogenesis developing within the perimatrix of the cholesteatoma of the pediatric patients was more expressed than that of the adult patients.

A review of current progress in acquired cholesteatoma management

The aim of this study was to review recent advances in the management of acquired cholesteatoma. All papers referring to acquired cholesteatoma management were identified in Medline via OVID (1948 to December 2013), PubMed (to December 2013), and Cochrane Library (to December 2013). A total of 86 papers were included in the review. Cholesteatoma surgery can be approached using either a canal wall up (CWU) or canal wall down (CWD) mastoidectomy with or without reconstruction of the middle ear cleft. In recent decades, a variety of surgical modifications have been developed including various "synthesis" techniques that combine the merits of CWU and CWD. The application of transcanal endoscopy has also recently gained popularity; however, difficulties associated with this approach remain, such as the need for one-handed surgery, the inability to provide continuous irrigation/suction, and limitations regarding endoscopic accessibility to the mastoid cavity. Additionally, several recent studies have reported successes in the application of laser-assisted cholesteatoma surgery, which overcomes the conflicting goals of eradicating disease and the preservation of hearing. Nevertheless, the risk of residual disease remains a challenge. Each of the techniques examined in this study presents pros and cons regarding final outcomes, such that any pronouncements regarding the superiority of one technique over another cannot yet be made. Flexibility in the selection of surgical methods according to the context of individual cases is essential in optimizing the outcomes.

Imaging review of the temporal bone: part I. Anatomy and inflammatory and neoplastic processes

From a clinical-radiologic standpoint, there are a limited number of structures and disease entities in the temporal bone with which one must be familiar in order to proficiently interpret a computed tomographic or magnetic resonance imaging study of the temporal bone. It is helpful to examine the region in an organized and systematic fashion, going through the same checklist of key structures each time. This is the first of a two-part review that provides a practical approach to understanding temporal bone anatomy, localizing a pathologic process with a focus on inflammatory and neoplastic processes, identifying pertinent positives and negatives, and formulating a differential diagnosis.

Identification of novel cholesteatoma-related gene expression signatures using full-genome microarrays

Background

Cholesteatoma is a gradually expanding destructive epithelial lesion within the middle ear. It can cause extensive local tissue destruction in the temporal bone and can initially lead to the development of conductive hearing loss via ossicular erosion. As the disease progresses, sensorineural hearing loss, vertigo or facial palsy may occur. Cholesteatoma may promote the spread of infection through the tegmen of the middle ear and cause meningitis or intracranial infections with abscess formation. It must, therefore, be considered as a potentially life-threatening middle ear disease.

Methods and Findings

In this study, we investigated differentially expressed genes in human cholesteatomas in comparison to regular auditory canal skin using Whole Human Genome Microarrays containing 19,596 human genes. In addition to already described up-regulated mRNAs in cholesteatoma, such as MMP9, DEFB2 and KRT19, we identified 3558 new cholesteatoma-related transcripts. 811 genes appear to be significantly differentially up-regulated in cholesteatoma. 334 genes were down-regulated more than 2-fold. Significantly regulated genes with protein metabolism activity include matrix metalloproteinases as well as PI3, SERPINB3 and SERPINB4. Genes like SPP1, KRT6B, PRPH, SPRR1B and LAMC2 are known as genes with cell growth and/or maintenance activity. Transport activity genes and signal transduction genes are LCN2, GJB2 and CEACAM6. Three cell communication genes were identified; one CDH19 and two from the S100 family.

Conclusions

This study demonstrates that the expression profile of cholesteatoma is similar to a metastatic tumour and chronically inflamed tissue. Based on the investigated profiles we present novel protein-protein interaction and signal transduction networks, which include cholesteatoma-regulated transcripts and may be of great value for drug targeting and therapy development.

Evaluation of epithelial proliferation in paediatric and adult cholesteatomas using the Ki-67 proliferation marker

INTRODUCTION

The aggressiveness of cholesteatoma in children compared with adults is well known. However, the factors influencing the poorer prognosis of paediatric cholesteatoma are not well understood. This study compared the proliferative potential of paediatric cholesteatoma with that of adult cholesteatoma, using Ki-67 as a proliferation marker.

METHODS

A prospective study of 67 patients with aural cholesteatoma was performed. Thirty-eight adult and 29 paediatric cases were evaluated using clinical parameters including bone erosion, complications and extent of disease. A surgical specimen underwent histological evaluation and measurement of the proliferation index using Ki-67 labelling. Normal epithelium from a control group was also examined.

RESULTS

Cholesteatoma epithelium has a greater rate of proliferation than normal skin. There were however no statistical differences between the paediatric and adult cholesteatoma groups in terms of clinical behaviour or proliferation potential. Paediatric cholesteatoma was similar to adult cholesteatoma in terms of complications, bone erosion and disease spread.

CONCLUSION

Cholesteatoma is a disorder of epithelial proliferation. Although postulated to be more aggressive in children than adults, this study found no clinicopathological differences between paediatric and adult cases.