Perspective on Temporomandibular Joint Disorder: Foramen Tympanicum Defect.

BACKGROUND: Foramen tympanicum (FT) is a defect located anterior-inferior to the external acoustic meatus. We evaluated its prevalence, location, size, and relationship with temporomandibular joint (TMJ) disorders. METHODS: Cone beam computed tomography was performed for 200 patients who presented to the Karamanoglu Mehmetbey University Ahmet Kelesoglu Faculty of Dentistry Hospital. The location and size of the FT in the axial and sagittal planes were evaluated. Descriptive statistics were used to compare the study parameters among age and sex groups. Patients with FT were reevaluated by two maxillofacial surgeons at the study centre. RESULTS: In total, 200 images from 400 joints were examined. Unilateral and bilateral FT (19 [9.5%] and 8 [4%], respectively) was detected in 35 (17.5%) images from 27 (13.5%) patients. Examinations were performed for TMJ disorders in 24 patients. Participants with bilateral defects had the highest rates of presence of sounds and ear pain on the left and right sides (p < .05). CONCLUSION: Foramen tympanicum can lead to TMJ disorders and spread of tumours or infections from the external auditory canal to the infratemporal fossa. The increased prevalence of such disorders in patients with bilateral FT suggests an association between them.

Chronic otorrhea and osteomyelitis of the external auditory canal by Achromobacter xylosoxidans: an uncommon diagnosis.

PURPOSE: Achromobacter xylosoxidans is an emerging pathogen mainly associated with resistant nosocomial infections. This bacteria had been isolated in the ear together with other pathogens in cultures from patients with chronic otitis media, but it had never been reported as a cause of osteomyelitis of the external auditory canal. CASE PRESENTATION: We present a unique case of a healthy 81-year-old woman who presented with left chronic otorrhea refractory to topical and oral antibiotic treatment. Otomicroscopy revealed an erythematous and exudative external auditory canal (EAC) with scant otorrhea. The tympanic membrane was intact, but an area of bone remodeling with a small cavity anterior and inferior to the bony tympanic frame was observed. Otic culture isolated multi-drug-resistant A. xylosoxidans, only sensitive to meropenem and cotrimoxazole. Temporal bone computed tomography showed an excavation of the floor of the EAC compatible with osteomyelitis. Targeted antibiotherapy for 12 weeks was conducted, with subsequent resolution of symptoms and no progression of the bone erosion. CONCLUSIONS: Atypical pathogens such as A. xylosoxidans can be the cause of chronic otitis externa. Early diagnosis and specific antibiotherapy can prevent the development of further complications, such as osteomyelitis. In these cases, otic cultures play an essential role to identify the causal germ. This is the first case of EAC osteomyelitis due to A. xylosoxidans reported to date.

[Unusual presentation of a mast cell tumor in the ear canal of a cat]. / Ungewöhnlicher Mastzelltumor im Gehörgang einer Katze.

A 12-year-old male neutered European Shorthair cat was presented for pruritus in the right ear region, bleeding from ear canal and a suspected polyp-like mass in its lumen.After the diagnostic imaging a biopsy of the mass was taken and submitted for histopathological evaluation. Histopathologic examination led to the diagnosis of low grade mast cell tumor. The subsequent staging examinations included ultrasonography of the liver and spleen as well as a complete blood count. Total ear canal ablation was performed on the same day, and the removed ear canal was again submitted for histopathologic evaluation of the surgical margins. The excision incision margins were free from infiltrating tumor cells. The cat was euthanised 14 months after the surgery. It is unknown whether the reasons for this were associated to metastatic spread of the initial mast cell tumor.A mast cell tumor in the ear canal is an unusual and rare finding, however it should be included in the list of differential diagnoses for ear canal tumors.

Congenital Anomalies of the Ear Canal.

Congenital anomalies of the external auditory canal (EAC) are classically divided into congenital aural atresia (CAA) and congenital aural stenosis (CAS). CAA can present as an isolated anomaly, unilateral or bilateral, or in the setting of a craniofacial syndrome. Hearing testing (ABR with air and bone conduction thresholds for both ears) early in the perinatal period is important to document hearing thresholds. Hearing status thus informs parent counseling on options for hearing habilitation: Bone conducting technology is a must for children with bilateral CAA to support normal speech and language development. Bone conducting technology should be considered for children with unilateral CAA; benefits are unclear. In select candidates, atresia repair can provide improved hearing with a clean, dry, epithelialized ear canal. First branchial cleft cyst or sinus is rare; high index of suspicion is needed to diagnose along with high-resolution CT. Congenital aural stenosis (CAS) is a rare condition, and hearing testing should be similar to that in children with CAA. Early (age 4-5) CT imaging is recommended in the setting of a canal <2 mm or pinpoint canal to evaluate for trapped skin/ear canal cholesteatoma.

Acquired Stenosis of the External Ear Canal.

Acquired stenosis of the external ear canal (ASEEC) is a relatively uncommon condition. Stenosis or narrowing of the external ear canal (EEC) occurs lateral to the tympanic membrane resulting in a skin lined blind canal. Recurrent otorrhea, and conductive hearing loss are typical clinical features. Although ASEEC can be due to different etiologies, a common pathogenesis, namely an inflammatory cascade, has been implicated. Clinical evaluation, audiogram, and Computed tomography (CT scan) form the mainstay of diagnosis. Surgery is the primary modality for treatment. Restenosis is the most common postsurgical complication.

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.

Foreign Body Granuloma Originating From the Lateral Process of Malleus: A Case Series of 19 Children.

OBJECTIVE: A special presentation of foreign body granuloma originating from the lateral process of the malleus (FBGLP) was noted in the absence of a history of foreign body entry into the external auditory canal (EAC). This study reported the clinical features, pathology, and prognosis of patients with FBGLP. DESIGN: Retrospective study. SETTING: Shandong Provincial ENT Hospital. PATIENTS: Nineteen pediatric patients (age, 1-10 yr) with FBGLP. INTERVENTIONS: Clinical data were collected from January 2018 to January 2022. MAIN OUTCOME MEASURES: Clinicopathologic characteristics of the patients were analyzed. RESULTS: All patients had an acute course, and were within 3 months of ineffective medical treatment. The most common symptoms were suppurative (57.9%) and hemorrhagic (42.1%) otorrhea. FBGLP imaging examinations demonstrated a soft mass blocking the EAC without bone destruction and occasionally concomitant effusion in the middle ear. The most common pathologic findings were foreign body granuloma (94.7%,18/19), granulation tissue (73.7%, 14/19), keratotic precipitate (73.7%, 14/19), calcium deposition (63.2%, 12/19), hair shafts (47.4%, 9/19), cholesterol crystals (5, 26.3%), and hemosiderin (15.8%, 3/19). Foreign body granuloma and granulation tissue showed higher expression levels of CD68 and cleaved caspase-3 than did the normal tympanic mucosa, whereas Ki-67 levels were similarly low in all tissues. The patients were followed up for 3 months to 4 years without recurrence. CONCLUSION: FBGLP is caused by endogenous foreign particles in the ear. We recommend the trans-external auditory meatus approach for FBGLP surgical excision, as this shows promising outcomes.

Colesteatoma del conducto auditivo externo: Experiencia de 5 años Hospital del Salvador / External ear canal cholesteatoma: 5-year experience Hospital del Salvador

Introducción: El colesteatoma del conducto auditivo externo (CCAE) es una estructura quística revestida por epitelio escamoso estratificado queratinizado que tiene la capacidad de invadir y erosionar localmente al hueso temporal. Su incidencia es de 0,19 a 0,3/100.000 habitantes siendo 60 veces menos frecuente que el de oído medio. Objetivo: Describir las características epidemiológicas, clínicas, imagenológicas y tratamiento de los pacientes diagnosticados con CCAE en el Servicio de Otorrinolaringología Hospital del Salvador. Material y Método: Se presenta una serie de ocho casos clínicos recopilados durante el período 2017 y 2021. Se realizó revisión de fichas clínicas, biopsias y tomografías computadas de oídos (TC oídos). Se describen los hallazgos y tratamiento efectuado. Resultados: El promedio de edad fue de 65,6 años, correspondiente a 5 mujeres y 3 hombres con presencia de tabaquismo y diabetes en la mitad de los casos. Los síntomas y signos más frecuentes fueron otalgia e hipoacusia seguido de otorrea. 7 pacientes se presentaron con tímpano íntegro y el compromiso de la pared inferior del conducto se evidenció en 6 de 8 pacientes. La TC oídos mostró erosión ósea del conducto, con o sin compromiso de estructuras adyacentes, en todos los casos y el diagnóstico histológico fue efectuado en el 100% de los pacientes. Se privilegió el tratamiento conservador mediante curaciones óticas periódicas asociado a ácido salicílico al 3% y/o antibióticos tópicos en 6/8 pacientes. Conclusiones: El CCAE es una entidad poco frecuente sin signos ni síntomas patognomónicos por lo que el diagnóstico histológico junto con el estudio imagenológico es perentorio. El tratamiento conservador es una alternativa terapéutica válida que ofrece buenos resultados en pacientes con adecuada adherencia al tratamiento y posibilidad de seguimiento estricto.

Introduction: External ear canal cholesteatoma (EECC) is a cystic structure lined by keratinized stratified squamous epithelium that has the ability to locally invade and erode the temporal bone. Its incidence is 0.19 to 0.3 / 100,000 habitants, being 60 times less frequent than that of the middle ear. Aim: To describe the epidemiological, clinical, imaging and treatment characteristics of patients diagnosed with EECC in the Hospital del Salvador ENT department. Material and Methods: A series of eight clinical cases collected during the period 2017 and 2021 is presented. A review of clinical records, biopsies and computed tomography of the ear (ear CT) was carried out. The findings and treatment carried out are described. Results: The average age was 65.6 years corresponding to 5 women and 3 men with the presence of smoking and diabetes in half of the cases. The most frequent symptoms and signs were earache and hearing loss followed by otorrhea. 7 patients presented with an intact eardrum and compromise of the inferior wall of the canal was evidenced in 6 of 8 patients. Ears CT showed bone erosion of the canal with or without compromise of adjacent structures in all cases and the histological diagnosis was made in 100% of the patients. Conservative treatment with periodic ear dressings associated with 3% salicylic acid and / or topical antibiotics was favored in 6/8 patients. Conclusion: EECC is a rare entity without pathognomonic signs or symptoms, therefore the histological diagnosis together with the imaging study is peremptory. Conservative treatment is a valid therapeutic alternative that offers good results in patients with adequate adherence to treatment and the possibility of strict follow-up.

Management of External Auditory Canal Anterior Wall Defect: A Case Series and Literature Review.

OBJECTIVES: Although rare in etiology, anterior bony wall defects of the external auditory canal (EAC) accompanied by temporomandibular joint herniation may cause various otologic symptoms. Surgical treatment can be considered based on symptom severity because many previous case reports have highlighted its efficacy. This study aimed to review the long-term results of surgical treatment of EAC anterior wall defect and to suggest a stepwise approach when creating a treatment plan. METHODS: We performed a retrospective review of 10 patients who underwent surgical management to address the EAC anterior wall defect and its associated symptoms. Medical records, temporal bone computed tomography scans, audiometry, and endoscopic examination findings were analyzed. RESULTS: The primary repair of the EAC defect was the first to be surgically addressed in most cases, excluding one case with a severe combined infection. Of the 10 cases, 3 patients exhibited either postoperative complications or symptom recurrence. Six patients had resolved symptoms consequent to primary surgical repair, and four patients underwent revision surgery undergoing a more invasive procedure, such as canalplasty or mastoidectomy. CONCLUSION: Primary repair of the anterior wall defect of the EAC seems to be overpromoted for lasting results but is not as promising as previously noted. We therefore propose to create a novel treatment flowchart regarding the surgical treatment of anterior wall defects of the EAC based on clinical experience. LEVEL OF EVIDENCE: IV.

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.

Malignant Melanoma of the External Auditory Canal on 68 Ga-FAPI PET/CT.

ABSTRACT: External ear melanomas are relatively rare and usually occur in the regions of helix and ear lobes. Rarer still are primary melanomas of the external auditory canal. We report findings of melanoma of the external auditory canal on 68 Ga-FAPI PET/CT in a 56-year-old man who presented with sharp pain in the external auditory canal for 7 months.

Clinical manifestations and treatment strategies for congenital aural atresia with temporomandibular joint retroposition: a retrospective study of 30 patients.

BACKGROUND: Patients with congenital aural atresia (CAA) can present with concomitant temporomandibular joint (TMJ) retroposition, implying that even with a high Jahrsdoerfer score, canaloplasty and tympanoplasty cannot be performed. Therefore, this study aimed to summarize the clinical manifestations and share our diagnostic and treatment experience of this rare entity, which has not been described previously. METHODS: Thirty patients (30 ears) with CAA and TMJ retroposition without maxillofacial dysplasia were included. Diagnosis was based on patient history, physical examination, pure-tone average test results, and temporal bone high-resolution computed tomography (HRCT) findings. Their Jahrsdoerfer scores and interventions were also recorded. RESULTS: Twenty-four and six patients among the 30 patients (males, n = 15) had CAA and TMJ retroposition on the right and left sides, respectively. Seventeen ears had a normal auricle; most had an enlarged cavum conchae and a large tragus. Twelve ears had an accessory auricle, and two had a preauricular fistula. All external auditory canals had complete atresia, including four with a shallow concavity and four with a small orifice in the cavum conchae. Temporal bone HRCT revealed poor or undeveloped tympanic temporal bone in the diseased ears, atresia in the external auditory canals, and partial/complete occupation of the mandibular condyle with or without soft tissue. The average Jahrsdoerfer score was 8.17. Thirteen patients opted for different surgeries, three wore a bone-conduction hearing aid, and fourteen chose no intervention. CONCLUSIONS: CAA with TMJ retroposition was often unilateral, typically on the right side. Most patients had normal auricles, with an enlarged cavum conchae and a large tragus ("mirror ear"). Even with a high Jahrsdoerfer score, traditional hearing reconstruction surgery could not be performed. Patients can undergo Vibrant Soundbridge or Bonebridge implantation or wear bone-conduction hearing aids to improve hearing levels, or refuse intervention because of mild hearing loss. The TMJ location can be used as a Jahrsdoerfer Grading System supplement for preoperative evaluation.

External auditory canal and middle ear tumors: characterization by morphology and diffusion features on CT and MRI.

PURPOSE: To explore the value of morphology and diffusion features on CT and MRI in the characterization of external auditory canal and middle ear tumors (EAMETs). METHODS: Forty-seven patients with histologically proved EAMETs (23 benign and 24 malignant) who underwent CT and MRI were retrospectively analyzed in this study. CT and MRI characteristics (including size, shape, signal intensity, border, enhancement degree, and bone changes) and apparent diffusion coefficient (ADC) value were analyzed and compared between benign and malignant EAMETs. Logistic regression, receiver operating characteristic (ROC) curve, and Delong test were performed to assess the diagnostic performance. RESULTS: Compared with benign tumors, the malignant EAMETs are characterized by irregular shape, ill-defined border, invasive bone destruction, and intense enhancement (all p < 0.05). There were no significant differences on the size and signal intensity between benign and malignant tumors. The ADC value of malignant tumors were (879.96 ± 201.15) × 10-6 mm2/s, which was significantly lower than benign ones (p < 0.05). Logistic regression demonstrates the presence of ill-defined margin, invasive bone destruction, and low ADC value (≤ 920.33 × 10-6 mm2/s) have significant relationship with malignant EAMETs. The combination of characterization by morphology and diffusion features on CT and MRI can further improve the diagnostic efficiency when compared with morphology and diffusion features alone (both p < 0.05). CONCLUSION: Some CT and MRI characteristics are helpful in identifying malignant EAMETs from benign ones (especially ill-defined margin, invasive bone destruction, and low ADC value), and the combination of morphology and diffusion features on CT and MRI has best diagnostic efficiency for discriminating these two entities.

Descriptive study of goat external and middle ear through computed tomography and endoscopic evaluation, compared with the human ear.

OBJECTIVE: To describe the external and middle ear of goats, using computed tomography and endoscopic dissection, comparing them with the anatomy of the human ear, aiming to evaluate the viability of this animal model for training in otological endoscopic surgery. METHODS: Images of the external and middle ear of goats were produced by computed tomography in the coronal and axial planes and analyzed. The radiological anatomy of the external and middle goat and human ear are described. Some measures of surgical interest were described, such as the length of the external auditory canal, external and internal cross-sectional area of the external auditory canal, middle ear depth, vertical angle of the external auditory canal, length of malleus and incus. After the tomographic study, we analyzed the importance of evaluations through the endoscopic dissection of the goat ear. RESULTS: The bony canal is extremely tortuous and shows a bony prominence with significant elevation near the lower edge of the tympanic membrane. The middle ear has a large tympanic bulla in the hypotympanum region. The malleus is shaped similarly to that of the human, but its handle is located anterior to its head. The mastoid is not pneumatized. Compared to the human mastoid, there was a statistically significant difference in the external and internal cross-sectional area, at the depth of the middle ear, in the vertical angle of the canal and in the length of the incus. CONCLUSION: Goat morphometric anatomy showed that this model is suitable for surgical simulation in the initial training for endoscopic otological surgery. It is an important contribution to the development of skills to accelerate the subsequent endoscopic otological surgical training in humans, despite some differences found.

Morphological relationships between external auditory canal and vital structures of tympanic cavity.

PURPOSE: We aimed to evaluate the morphology of the external auditory canal (EAC) using a three-dimensional (3D) reconstruction of computed tomography (CT) scans of the temporal bone to corroborate and predict important anatomical structures involved in middle ear surgery based on the EAC morphology. METHODS: Temporal bone CT from 62 patients (120 ears) was used to perform 3D reconstruction (maximum intensity projection), of which 32 patients (60 ears) had chronic otitis media and 30 patients (60 ears) had normal temporal bones. The anatomical morphology of the EAC, tympanic sinus, vertical portion of the facial nerve, and jugular bulb were measured, and the anatomical relationship between the EAC morphology and important structures of the middle ear was analyzed. RESULTS: In ears with chronic otitis media, the overhang of the inferior wall of the EAC was significantly more than that in normal ears, and the antero-posterior length of the bony tympanic ring was short. Furthermore, the tympanic sinus was shallow, and vertical portion of the facial nerve tended to run outward. The EAC morphology correlated with the tympanic sinus depth and outward orientation of the vertical portion of the facial nerve. CONCLUSION: A severe overhang of the inferior wall of the EAC and short antero-posterior length of the bony tympanic ring indicates a higher possibility of a shallow tympanic sinus and an outward orientation of the vertical portion of the facial nerve. These findings aid in predicting the difficulty of tympanic sinus operation and reducing facial nerve damage risk during EAC excision.

Clinical Analysis of 85 Cases of External Auditory Canal Cholesteatoma Surgery under Specialized Endoscopy.

Objective: To investigate the clinical characteristics, surgical experience, and surgical outcomes of external auditory canal cholesteatoma (EACC) surgery under endoscopic otolaryngoscopy. Methods: A retrospective analysis of 85 EACC cases admitted to the Department of Otolaryngology, Renji Hospital, Shanghai Jiaotong University School of Medicine, from January 2016 to February 2021 was performed, followed by retrospective analysis of clinical data to explore the feasibility and clinical characteristics of all-oral endoscopic EACC surgery. A total of 85 EACC patients (90 ears) with a mean age of 49.93 ± 14.87 years were included in the study. According to Udayabhanu staging, 43 ears (47.78%) were stage I, 40 ears (44.44%) were stage II, and 7 ears (7.78%) were stage III. All patients underwent transendoscopic surgery. Results: 79 ears (87.78%) underwent endoscopic EACC resection alone (+external auditory canal tumor resection/tympanostomy tube insertion), 9 ears (10%) underwent endoscopic EACC resection+tympanostomy+tympanoplasty, 1 ear (1.11%) underwent endoscopic EACC resection+tympanoplasty, and 2 ears (2.22%) underwent EACC resection+otolaryngotomy+tympanoplasty+auditory chain reconstruction endoscopically. Of these, 7 ears (7.78%) underwent auricular cartilage-chondroplasty and 2 ears (2.22%) underwent auricular cartilage membrane repair. All patients were reviewed at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year postoperatively. One patient with stage II external auditory atresia had a recurrence after 6 months and underwent endoscopic ear surgery (ESS) again. One patient with stage 2 atresia recurred after 1 year and again underwent endoscopic ear surgery. The rest of the patients recovered well after the surgery, and the grafts healed well. Conclusion: EACC surgery through the external ear canal under a dedicated endoscope is a safe, reliable, and effective method. Patients with stage I and II external auditory canal cholesteatoma surgery under endoscopy have a rapid postoperative recovery with significant hearing improvement, and stage IIIA patients can also achieve good results under strict evaluation of indications.

Quiste epidermoide en conducto auditivo externo: reporte de caso / Epidermoid cysts of the external auditory canal: case report

Resumen El quiste epidérmico es una lesión benigna y común de la piel. Se desarrolla por un bloqueo de la unidad pilosebácea, con la consecuente proliferación de células epiteliales y secuestro de queratina. El 7% se desarrollan en cabeza y cuello, sin embargo, son infrecuentes en canal auditivo externo. Su patrón de crecimiento es lento y progresivo durante años, siendo asintomáticos. Al aumentar de tamaño causan sintomatología variable, acorde a su localización; en el canal auditivo tienen un comportamiento obstructivo que genera síntomas como otalgia e hipoacusia. Se presenta caso de una paciente de 69 años, con acúfeno e hipoacusia progresiva derecha. Durante la otoscopia se observó una neoformación obstructiva del 100% de la luz del conducto. Se realizaron estudios de imagen que reportaron tumoración de características quísticas de conducto auditivo derecho, bien circunscrita, sin erosión ósea. Para el diagnóstico definitivo, se realizó resección quirúrgica y biopsia reportando quiste epidérmico. Durante el seguimiento posoperatorio sin hallazgos de recidiva.

Abstract The epidermal cyst is a common and benign lesion of the skin. It develops due to a blockage of the pilosebaceous unit, with the consequent proliferation of epithelial cells and keratin sequestration. Seven percent develop in the head and neck; however, they are infrequent in the external auditory canal. Its growth pattern is slow and progressive over the years, being asymptomatic. As they increase in size, they cause variable symptoms, according to their location. In the ear canal they have an obstructive behavior that generates symptoms such as earache and hearing loss. A case of a 69-year-old female with tinnitus and progressive right hearing loss is presented. At otoscopy, a 100% obstructive neoformation of the canal lumen was observed. Imaging studies showed a well circumscribed, cystic tumor of the right ear canal, without bone erosion. For the definitive diagnosis, a resection and biopsy were performed, reporting an epidermal cyst. During follow up there was no recurrence of tumor.

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.