Cholesteatoma remains a prevalent otologic condition worldwide, with a notably high incidence in developing nations. Initially defined in 1959 by Freidman as a well-defined cyst covered by stratified squamous epithelium of variable thickness, our understanding of the pathology has evolved.[1] Contemporary literature defines it as an abnormal, noncancerous growth that forms behind the tympanic membrane. Pathophysiologically, it is driven by the keratinization of squamous epithelium into a sac-like structure within the middle ear cleft, often colloquially referred to as "skin in the wrong place."[2]

Despite its benign histological classification, cholesteatoma exhibits locally invasive properties and possesses a high potential for recurrence. It remains a significant cause of pediatric morbidity and mortality, particularly in low-resource settings lacking advanced healthcare infrastructure. While superficial aspects of the disease can be detected clinically via otoscopic examination, the deeper extensions of the cholesteatoma into the attic, antrum, and mastoid air cells remain entirely obscured from direct view. Furthermore, critical anatomical zones such as the epitympanic recess, sinus tympani, and facial recess cannot be visualized clinically, making the disease prone to being missed during conservative surgical approaches. Therefore, efficient and complete evacuation of the disease is absolutely essential to prevent relapse and complications. [2,3]

High Resolution Computed Tomography (HRCT) serves as the confirmatory diagnostic standard for temporal bone cholesteatoma, complementing the initial clinical examination. HRCT’s precise ability to predict the status of involved hidden areas and document subtle bony erosions is vital for determining the true extent of the disease, thereby helping surgeons avoid severe intraoperative complications. [4,5] This study was explicitly undertaken to assess these clinically hidden areas utilizing HRCT, mapping the extent and behavioral patterns of cholesteatoma in a designated patient cohort.

Clinical Features and Symptomatology

The clinical presentation of cholesteatoma is highly variable, largely depending on the stage and extent of the disease.

• Asymptomatic Presentation: In its nascent stages, the disease may remain entirely asymptomatic, delaying diagnosis.
• Otorrhea (Ear Discharge): Persistent, malodorous discharge is a hallmark symptom. This putrid odor is typically secondary to anaerobic bacterial infection. The discharge is usually purulent yet scanty—often so minimal that the patient may be unaware of its presence. Notably, the sudden cessation of discharge in a chronically discharging ear is considered an ominous sign, as it may indicate that the perforation has been sealed by crusted debris or a polyp, obstructing the free flow of purulent material and increasing the risk of intracranial complications.

• Progressive Hearing Loss: Patients frequently experience slowly progressive conductive hearing loss. Hearing may remain relatively preserved if the ossicular chain is intact, or paradoxically, if the cholesteatoma mass itself bridges the gap between destroyed ossicles (cholesteatoma hearer). Over time, a sensorineural component may be superimposed.
• Aural Bleeding: Bleeding can occur secondary to trauma to friable granulation tissue or aural polyps during ear cleaning.
• Sequelae Symptoms: Advanced disease encroaching on surrounding structures may manifest as localized pain, vertigo, facial nerve palsy, chronic headache, vomiting, ataxia, and fever. [6,7]

Otoscopy, Microscopy, and Endoscopy Findings

Clinical examination often reveals specific localized changes:

• Perforation: Marginal perforations in the attic and posterosuperior regions are classical findings. Attic perforations may be obscured by small crusts.
• Retraction Pockets: Invaginations in the attic and posterosuperior pars tensa vary from shallow, self-cleansing pockets to deep, debris-filled spaces.
• Cholesteatoma Presentation: Pearly white keratin flakes are typically visible within these retraction pockets.

o              Primary Acquired: Involves defects of variable size in the attic/posterosuperior region containing keratin.

o              Secondary Acquired: Characterized by migrating keratinizing epithelium entering the middle ear through a pre-existing perforation.

o              Congenital: Presents as a pearl-like mass behind a perfectly intact tympanic membrane.

• Granulation and Polyps: Fleshy red aural polyps or granulation tissue often surround areas of osteitis. Aural polyps in chronic otorrhea must be managed with a high index of suspicion for underlying cholesteatoma.
• Ossicular Necrosis: Visible destruction often involves the long process of the incus, the stapes superstructure, and the handle of the malleus.
• Fistula Test: A positive test suggests erosive involvement of the lateral semicircular canal. [8]

Audiological Investigations

Preoperative audiological assessment is mandatory to categorize the degree and type of hearing loss.

• Tuning Fork Tests (TFTs): Utilizing 256, 512, and 1024 Hz forks allows for the differentiation of conductive versus sensorineural loss through tests such as Rinne's, Weber's, and the Absolute Bone Conduction (ABC) test.
• Pure Tone Audiometry (PTA): Provides a subjective graphical representation of hearing thresholds. By mapping air conduction (125-8000 Hz) and bone conduction (250-4000 Hz), the air-bone gap (A-B gap) is calculated. An A-B gap greater than 20 dB across consecutive frequencies strongly indicates conductive deafness.
• Impedance Audiometry: Analyzes the middle ear's efficiency as an impedance-matching device. Eustachian tube function tests (like the Williams test) evaluate resting and dynamic middle ear pressures. Additionally, acoustic reflex testing monitors the reflex contractions of the stapedius and tensor tympani muscles, providing objective data on middle ear compliance. [9]

The Role of HRCT in Temporal Bone Evaluation

The application of HRCT in atticoantral disease, particularly in the absence of obvious intracranial complications, has historically been debated. However, it is now widely accepted that HRCT is paramount for surgical planning and anticipating complications. HRCT effectively details the extent of bone destruction, the degree of mastoid pneumatization, the position of the dura (e.g., low-lying dura), and the placement of the sigmoid sinus.

In CT scans, cholesteatoma typically presents as a non-dependent soft tissue attenuation within the middle ear cleft. While HRCT cannot entirely differentiate between simple mucosal disease or fluid and a cholesteatoma matrix, its ability to delineate extensions into the epitympanum, mesotympanum, sinus tympani, and antrum is critical for both the anatomical and audiological success of subsequent surgeries. [9,10]

Surgical Management

The primary therapeutic modality is surgical, aimed at eradicating the disease and rendering the ear "safe." Secondary objectives include hearing preservation and reconstruction. The primary surgical avenues are:

1. Canal Wall-Up (Closed) Procedure: Approaches the disease through the external auditory canal (EAC) and mastoid, keeping the posterior canal wall intact. It preserves native anatomy and reduces postoperative care but carries a higher risk of residual/recurrent disease.
2. Canal Wall-Down (Open) Procedure: Exteriorizes the mastoid cavity and EAC into one continuous space (e.g., Radical or Modified Radical Mastoidectomy). This is definitive for aggressive disease but requires lifelong cavity care. [11,12].

Study Design and Setting

A prospective, observational clinical study was conducted in the Department of Otorhinolaryngology (ENT) at the Basaveshwara Teaching and General Hospital, attached to Mahadevappa Rampure Medical College, Kalaburagi. The study spanned 18 months, from August 1, 2022, to January 31, 2024.

Study Population and Sampling

The study comprised a sample size of 50 patients who were clinically diagnosed with cholesteatoma. Patients were evaluated preoperatively with routine investigations, including an HRCT of the temporal bone.

Inclusion Criteria:

• Patients with a confirmed clinical diagnosis of cholesteatoma.
• Patients of all age groups.

Exclusion Criteria:

• Presence of congenital malformations in any part of the ear.
• History of previous ear surgeries (revision cases).
• History of direct trauma to the temporal bone.

Data Collection Procedure

Institutional ethics committee approval was secured prior to the commencement of the study. Informed consent was obtained from all participating subjects or their guardians. Diagnosis was established via rigorous clinical and otoscopic/microscopic evaluation. High-resolution temporal bone images were then obtained. In subjects presenting with bilateral disease, each middle ear was treated as a distinct statistical entity and evaluated independently.

Imaging Technique

Imaging was performed utilizing a Philips 16-slice CT scanner. High-resolution coronal, axial, and sagittal images were acquired with the following parameters: 20 × 0.625 collimation, 0.8 mm thickness, 320 mAs, and 120 kVp. Ultra-thin image reconstruction was achieved using a high-resolution bone algorithm in the axial plane (0.5 mm section thickness, 0.01 mm increments) with a Field of View (FOV) of 100 and a matrix size of 512 × 512. DICOM images were interpreted on a 3D workstation using RadiAnt software (version 2023.1). A total of 100 high-resolution temporal bone studies (bilateral scans for 50 patients) were meticulously evaluated.

Statistical Analysis

Quantitative and qualitative data were compiled in master charts and subjected to statistical analysis using IBM SPSS Version 28.0.1.0 software. The Chi-Square test was employed for qualitative data associations, with a p-value of <0.05 considered statistically significant.

This study successfully mapped the involvement of cholesteatoma in the middle ear and its hidden recesses utilizing HRCT in a cohort of 50 subjects.

Demographic Distribution

The patient cohort exhibited a wide age range from 6 to 69 years, with a mean age of 32.84 ± 15.95 years. The highest incidence was noted in the second decade of life (11–20 years), accounting for 28% (n=14) of the cases, followed closely by the 31–40 years age bracket (26%, n=13).  Males constituted the majority of the cohort. (64%, n=32) compared to females (36%, n=18), resulting in a male-to-female ratio of 1.8:1. A Chi-square analysis comparing age groups across gender yielded a value of 5.196, which was not statistically significant (p = 0.52).

Table 1: Comparison between age groups and gender

Laterality and Symptomatology

The disease displayed equal lateralization, affecting the right and left ears equally. Bilateral disease was documented in 4 patients (8%); however, for statistical modeling, these were calculated to maintain the sample standard of 50 analyzed pathological ears. The clinical symptomatology was largely uniform: otorrhea was the most dominant complaint, reported by 96% (n=48) of patients. This was followed by hearing loss (80%, n=40), ear pain (76%, n=38), and tinnitus (42%, n=21). Vertigo was present in 18% (n=9) of subjects.

Table 2: Chief complaints of the study subjects

Soft Tissue Density and Anatomical Involvement

HRCT findings demonstrated multi-focal soft tissue involvement. The epitympanum was universally opacified in all 50 (100%) subjects. This was heavily associated with the invasion of Prussak’s space in 42 (84%) cases. Aditus and antrum involvement was equal, seen in 40 (80%) subjects respectively.

Table 3: Soft tissue density at different locations on HRCT

Ossicular Chain Status and Bony Erosions

The integrity of the ossicular chain is paramount for surgical planning. HRCT demonstrated the classic "ice cream cone" appearance (suggesting intact malleus-incus articulation) in 31 (62%) cases. Conversely, the stapes supra-structure was visualized in 40% (n=20), and the "two dot sign" was seen in 14% (n=7).

Regarding bony erosion, the incus was the most vulnerable, demonstrating erosions in 86% (n=43) of the cases. The stapes was eroded in 60% (n=30), malleus in 38% (n=19), and the scutum in 24% (n=12) of cases.

Table 4: Location of bony erosions

Mastoid Pneumatization and Cellular Involvement

Evaluation of mastoid air cells indicated significant cellular attenuation, predominantly in the mastoid antrum and periantral cells (48%, n=24 for both). Classification of mastoid pneumatization revealed that 52% (n=26) of the diseased temporal bones were sclerotic, reflecting long-standing chronic inflammatory disease, whereas 34% (n=17) were diploeic, and only 14% (n=7) were well-pneumatized.

Extension into Hidden Spaces

A critical objective of this study was mapping disease in hidden recesses. 60% of the cohort (n=30) demonstrated invasion into at least one hidden anatomical space. Specifically, the sinus tympani and the facial recess were equally involved in 30% (n=15) of cases each, while the anterior epitympanic recess was involved in 14% (n=7).

Extensions beyond the anatomical boundaries of the middle ear cleft were rare but significant. Two cases (4%) exhibited destruction of the dural plate, and one case (2%) demonstrated sigmoid sinus plate destruction. No instances of lateral semicircular canal dehiscence were noted.

The primary objective of the present study was to map the detailed topography of cholesteatoma expansion within the middle ear and its obscured recesses utilizing High-Resolution Computed Tomography (HRCT). Conducted at a tertiary care center, the data reinforces the established capability of HRCT as a mandatory preoperative tool in modern otologic practice.

While clinical examination, pure tone audiometry, and impedance audiometry provide functional and superficial structural data, they intrinsically fail to map the actual volumetric extent of a cholesteatoma matrix deep within the temporal bone. HRCT excels precisely where otoscopy fails: detecting early erosive changes in the ossicular chain and identifying soft tissue opacities in anatomically complex hidden zones like the sinus tympani, facial recess, and anterior epitympanic space. While it is acknowledged that HRCT cannot entirely differentiate cholesteatoma from granulation tissue, scar tissue, or organized fluid on the basis of density alone, its superior spatial resolution makes it more practical and economical than MRI or PET-CT for routine preoperative assessment of bony architecture.

In our cohort of 50 patients, the disease demonstrated a strong propensity for younger demographics, with the highest prevalence in the 11–20 years age group (28%) and a mean age of 32.84 years. This suggests that acquired cholesteatomas often develop and become symptomatic during late childhood and early adulthood. The male predilection in our study (ratio of 1.8:1) aligns closely with similar epidemiological findings in the literature. For instance, a study by Saravanan et al. reported a male predominance of 60% with a sex ratio of 1.5.[13] Contrastingly, some studies, such as that by Uz Zaman et al., noted no gender disparity (1:1 ratio). Such regional variations underscore the heterogeneous environmental and potentially anatomical predispositions in different populations. [14]

Clinically, chronic otorrhea was nearly universal (96%) in our sample, heavily correlating with the extensive soft tissue disease mapped on HRCT. The epitympanum was universally involved (100%), which correlates seamlessly with the known pathophysiology of primary acquired cholesteatomas originating from pars flaccida retraction pockets. This further explains the high rate of incus erosion (86%) observed in our study, as the body of the incus resides prominently in the path of an expanding epitympanic cholesteatoma. The stapes was the second most affected ossicle (60%), followed by the malleus (38%).

The status of mastoid pneumatization in our cohort strongly reflected the chronic nature of the disease, with a majority (52%) demonstrating sclerotic mastoids. Chronic eustachian tube dysfunction and recurrent childhood otitis media lead to an arrest in mastoid air cell development, culminating in sclerosis; a finding highly prevalent in patients developing aggressive cholesteatoma. [15]

Crucially, HRCT confirmed hidden space involvement in 60% of our total cohort, a volume of disease that would have been entirely invisible to routine outpatient diagnostics. The 30% involvement of the sinus tympani is particularly notable; this region is notoriously difficult to visualize directly during standard surgical approaches and is a primary locus for residual disease leading to postoperative recurrence. Identifying this preoperatively mandates a surgical approach tailored to safely access and clear this recess[12-15].

The application of High-Resolution Computed Tomography is an indispensable element in the comprehensive evaluation of cholesteatoma. The present study effectively demonstrates that clinical examination vastly underestimates the structural damage and spatial footprint of the disease. By accurately defining the integrity of the ossicular chain; particularly the highly susceptible incus; and precisely mapping disease extension into hidden, surgically challenging areas like the sinus tympani and facial recess, HRCT provides the otologic surgeon with a vital roadmap. While lacking tissue-specific differentiation, its unparalleled depiction of temporal bone microarchitecture minimizes the risk of intraoperative surprises, enables the selection of appropriate surgical techniques (canal wall-up vs. canal wall-down), and ultimately aids in securing a safe, dry ear with optimal hearing preservation.

1. Coman M, Coman A, Gheorghe DC. All about imagistic exploration in cholesteatoma. Maedica. 2015;10(2):178.
2. Sergi CM. Head and Neck. InPathology of Childhood and Adolescence: An Illustrated Guide 2020 Oct 29 (pp. 1167-1241). Berlin, Heidelberg: Springer Berlin Heidelberg.
3. Haque MM, Shahrear K, Ikbal A. Pediatric vs Adult Cholesteatoma—A Study on Recurrence Rates and Surgical Challenges. The Insight. 2025 Oct 14;8(02):252-8.
4. Meena U. Imaging spectrum of temporal bone in cholesteatoma patients in a tertiary care hospital of central India by High Resolution Computed Tomography.
5. Baloiu AI, Filipoiu F, Toader C, Covache-Busuioc RA, Munteanu O, Serban M. Sphenoid sinus hyperpneumatization: anatomical variants, molecular blueprints, and AI-augmented roadmaps for skull base surgery. Frontiers in Endocrinology. 2025;16:1634206.
6. Melariri H, Balakrishna Y, Mukhtar A, Joseph E, Labuschagne S, Hapunda‐Chibanga R, Finestone S, Bosman A, Ukaegbe O, Werkineh HB, Merven M. The Global Burden of Cholesteatoma: A Systematic Review and Meta‐analysis. Otolaryngology–Head and Neck Surgery. 2026;174(1):45-56.
7. James AL, Fina M. Techniques in Management of Cholesteatoma: Endoscopic Approaches. Otolaryngologic Clinics of North America. 2025 Feb 1;58(1):99-112.
8. Forli F, Capobianco S, De Vito A, Bruschini L, Lazzerini F. Issues in the audiological assessment of otosclerosis. ACTA Otorhinolaryngologica Italica. 2025;45(3 Suppl 1):S40.
9. Pandey N, Ranjan RK, Rai N, Toppo SK, Xalxo AR, Agrawal R, Gourab K. HRCT Scan Evaluation of Temporal Bone Cholesteatoma and its Correlation with Peroperative Findings. Journal of Pharmacy and Bioallied Sciences. 2025;17(Suppl 2):S1341-3.
10. Singla K, Talha M, Gambhir M, Kumar P, Kumar H, Swami P, Ikram I, Krishna S, Gupta U. ROLE OF HIGH-RESOLUTION COMPUTED TOMOGRAPHY (HRCT) IN EVALUATION OF PATHOLOGIES OF TEMPORAL BONE: A CROSS SECTIONAL STUDY. International Journal of Medicine & Public Health. 2026;16(2):2327.
11. Han L, Tao Y, Yu L. Surgical Principles of Cholesteatoma. InProgress in Postauricular Administration 2026 Jan 20 (pp. 35-50). Singapore: Springer Nature Singapore.
12. Körmendy B, Kálmán J, Illés K, Fehérvári P, Wenning AS, Nagy R, Hegyi P, Simon F, Horváth T. Modeling residual cholesteatoma growth rate: a meta-analysis of individual participant data. European Archives of Oto-Rhino-Laryngology. 2026:1-2.
13. K Saravanan, Nithish Kumar Yeslawath, Shriram Thamaraiselvan. Role of HRCT temporal bone in cholesteatoma patients undergoing surgery. International Journal of Contemporary Medicine Surgery and Radiology. 2022;7(2):B43-B46.
14. Uz Zaman S, Rangankar V, Muralinath K, et al. Temporal Bone Cholesteatoma: Typical Findings and Evaluation of Diagnostic Utility on High Resolution Computed Tomography. Cureus. 2022;14(3):e22730.
15. Khan F. A Study of Correlation Between Clinical Features, Radiodiagnosis and Operative Findings in Chronic Suppurative Otitis Media with Cholesteatoma(Master's thesis, Rajiv Gandhi University of Health Sciences (India)).