|Year : 2020 | Volume
| Issue : 1 | Page : 36-39
Internal auditory canal osteoma: Wait or operate – Case report and literature review
Abdulaziz AlEnazi1, Houri Albalawi2, Ali Alhaidy3, Munahi Al-Qahtani4
1 Department of Otorhinolaryngology-Head and Neck Surgery, Imam Abdul Rahman Bin Faisal University, King Fahd Hospital of the University, Alkhobar, Saudi Arabia
2 College of Medicine, Princess Nourah Bint Abdul Rahman University, Riyadh, Saudi Arabia
3 Department of Radiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
4 Department of Otorhinolaryngology-Head and Neck Surgery, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
|Date of Submission||02-Nov-2019|
|Date of Decision||09-Dec-2019|
|Date of Acceptance||07-Feb-2020|
|Date of Web Publication||01-Jun-2020|
Dr. Abdulaziz AlEnazi
Department of Otorhinolaryngology.Head and Neck Surgery, Imam Abdul Rahman Bin Faisal University, King Fahd Hospital of the University, Alkhobar
Source of Support: None, Conflict of Interest: None
Internal auditory canal osteomas (IACOs) are rare, slow-growing, and benign bone tumors. They are most often found incidentally with few-reported cases. Osteomas involving the internal auditory canal (IAC) are particularly rare. The symptoms of the IACO usually arise due to direct pressure on the vestibulocochlear nerve; however, etiology, mechanism, and management remain unclear. The present report describes the rare case of IACO involving a 15-year-old male who was referred to a tertiary referral center with a history of chronic supportive otitis media, which was otherwise asymptomatic. The ensuing discussion and brief literature review address whether to wait or operate. IACO in this patient exhibited slow-growing features, and audiology assessment revealed no sensory neural hearing loss. Computed tomography (CT) revealed a round, radiopaque pedunculated bony outgrowth in the right IAC. Magnetic resonance imaging using a selected T2-weighted sequence revealed the osteoma projecting from the posterior superior aspect of the right IAC. Accordingly, clinical observation was recommended. Observation, including serial CT, is recommended for asymptomatic patients. Surgery is not advisable in slow-growing and asymptomatic cases because the risks are due to its dangerous location. Decisions regarding the management must consider according to symptom severity, progression, and risks in surgery. The question of whether to operate, therefore, should be carefully considered depending upon patient complaints and medical findings.
Keywords: Asymptomatic osteoma, internal auditory canal, observation, osteoma
|How to cite this article:|
AlEnazi A, Albalawi H, Alhaidy A, Al-Qahtani M. Internal auditory canal osteoma: Wait or operate – Case report and literature review. Saudi J Otorhinolaryngol Head Neck Surg 2020;22:36-9
|How to cite this URL:|
AlEnazi A, Albalawi H, Alhaidy A, Al-Qahtani M. Internal auditory canal osteoma: Wait or operate – Case report and literature review. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2020 [cited 2020 Jul 16];22:36-9. Available from: http://www.sjohns.org/text.asp?2020/22/1/36/285553
| Introduction|| |
Osteomas of the internal auditory canal (IAC) are rare and slowly progressive entities and uncommonly symptomatic. It is most often located in the facial sinuses or cranial vault, they are often clinically silent, lasting for years and may be diagnosed incidentally on a cerebral or facial computed tomography (CT) scan. The most common symptoms include unilateral sensorineural hearing loss, vertigo and less commonly, tinnitus, due to direct pressure on the vestibulocochlear nerve. Treatment options for IACOs are based mainly on symptom severity caused by nerve compression and to avoid irreversible complications. Surgical options have been described in the few cases reported in the literature, in which clinical improvement ruled out the consideration of surgical intervention. The site of these tumors should be considered because they are dangerous, and the risks for surgical complications are high. Nevertheless, a review of surgical outcomes for IACOs in a case series by Davis et al. described some improvement and all symptoms resolved. Surgical approaches depend on hearing level, location, and compression symptoms.,, To the best of our knowledge, there is no consensus regarding when or whether to operate on symptomatic or asymptomatic patients. The aim of the present report is to describe a rare, asymptomatic case of IACOs and discuss the decisions whether to operate or monitor clinically.
| Case Report|| |
A 15-year-old male was referred to the otology clinic with a history of chronic suppurative otitis media in both ears, which was treated successfully. He did not complain of dizziness, loss of balance, or facial weakness. In this case, the lesion was incidentally found. The patient denied any vertigo, tinnitus, facial weakness, or imbalance. He had no history of any chronic illnesses. Tympanometry revealed a flat Type B curve in both ears with normal ear-canal volume. Laboratory tests were also within normal limits. In January 2018, CT was prescribed during the workup and revealed an ossified process extending from the posterosuperior aspect of the right IAC projecting anteroinferiorly causing narrowing of medial aspect of the right IAC [Figure 1] and [Figure 2]. In addition, magnetic resonance imaging (MRI) of the head was performed [Figure 3] and [Figure 4]. A heavily T2-weighted MRI sequence of the IAC revealed the process as described on the CT scan. Coronal and sagittal oblique reformat imaging demonstrated the osteoma projecting from the posterior superior aspect of the right IAC. In addition, coronal T2 fat-saturated MRI [Figure 3] and [Figure 4] demonstrated the lesion projecting from the superior wall of the medial aspect of the right IAC, highlighting the known osteoma. In addition, patient denied any vertigo, tinnitus, facial weakness, or imbalance. He had no history of any chronic illnesses. Tympanometry revealed a flat Type B curve in both ears with normal ear-canal volume. Laboratory tests were also within normal limits. pure-tone audiometry revealed bilateral moderate conductive hearing loss due chronic ear sequelae [Figure 5]a. Pure-tone audiometry was repeated 1 year later and revealed no significant progression or sensorineural hearing loss [Figure 5]b. In this case, regular follow-up for early recognition, regular clinical monitoring, and CT were imperative because surgical removal appeared to be too risky in such an asymptomatic patient.
|Figure 1: Axial computed tomographic scan describing osteoma of the right internal auditory canal|
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|Figure 2: A coronal computed tomographic scan showing a right internal auditory canal osteoma|
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|Figure 3: (a-c), Axial (d), coronal T2-weighted magnetic resonance imaging showing an osteoma in the right internal auditory canal|
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|Figure 4: Sagittal T2-weighted magnetic resonance imaging, Rt internal auditory canal osteoma|
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|Figure 5: (a) Pure-tone audiometry during the work up (b) Pure-tone audiometry during follow-up|
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| Discussion|| |
Osteomas are commonly found in the temporal bone. The most frequent locations of osteomas reported in the literature include external acoustic meatus, mastoid cortex, facial bones, and mandible., Osteomas found in the IAC are rare.,, Thefirst case of bilateral osteoma of the IAC was published in 2008 by Gerganov et al. There are no precise prevalence figures for IAC osteoma. The symptoms resemble acoustic-facial bundle involvement, including vestibular and hearing symptoms, such as unilateral sensorineural hearing loss, imbalance, vertigo, and tinnitus. Decisions regarding the management must consider the patient'sfirst complaints, progression, age, and wishes, as well as the risks of surgery. In addition, osteoma can be asymptomatic, lasting for years and incidentally found on radiography.,,, To exclude other rare bony cranial pathologies, it is essential to use both CT and MRI to diagnose an osteoma [Figure 1], [Figure 2], [Figure 3], [Figure 4]. The diagnosis of IACOs relies heavily on CT findings because it is a bone lesion. It is essential to examine the contour of the entire length of the IAC on the CT scan of the temporal bone. It has a characteristic radiological appearance, exhibiting a well-demarcated pedunculated dense bony outgrowth of the IAC. The lesion will appear with hypointense signal intensity on T2-weighted sequences., T1-weighted imaging with gadolinium also helpful because it helps to rule out other pathologies. It has been considered the gold standard for the diagnosis of IAC lesions. MRI demonstrates bright signal intensity in Tl-weighted imaging due to the presence of fat inside the bone marrow. Histology of an osteoma reveals discrete fibrovascular channels surrounded by lamellated bone with few osteocytes and lacunae. The presence of the Haversian canal is essential to differentiate an osteoma from an exostosis., The diagnosis can either be incidental or by the clinical presentation which is due to compression of the vestibulocochlear crania nerve. For symptomatic cases, the management of IAC osteoma is decided according to symptom severity. Patients presenting with severe symptoms or at risk for IAC damage may require surgical excision of the tumor to prevent irreversible complications. Our case also supports the etiological theory of osteomas caused by chronic middle ear inflammation with the objective reason of otitis history. However, in our case, there was no direct relationship or specific finding. In addition, as with any other surgery, patient age and wishes should be considered during the decision-making on whether to operate, as well as radiological findings. Furthermore, there is no consensus regarding the treatment of this entity, and close clinical monitoring is needed to avoid unexpected complications. Surgery is not advisable in asymptomatic cases because the risks in surgery are high due to its dangerous site. The patient in our case was young and asymptomatic, and there was no indication for surgical excision of the tumor.
IAC osteoma is a rare condition, and its natural history remains largely unknown. The treatment of IAC osteomas remains controversial. Many authors agree that the treatment approach should be determined according to symptom severity. However, the literature reports that stable clinical presentation can be managed conservatively with a trial of watchful waiting. Schutt et al. reported that there was no progression of bony narrowing of the porus acusticus over a 12-year period. The treatment of IAC osteomas depends on clinical presentation. Surgery is not advisable in asymptomatic cases because the risks are high due to its dangerous location. After reviewing the literature published since 1979, expectant management with observation, including serial CT scans, is recommended for asymptomatic IAC. Davis et al. reported a symptomatic case of right IAC osteoma that initially presented with vertigo and right aural fullness, in which the patient was managed by clinical monitoring and experienced symptom resolution with no tumor progression over a period of 4.5 years. Vrabec et al. described a case with the longest follow-up period (5 years), with no change in tumor size or progression of symptoms after clinical monitoring. Additional studies with longer-term follow-up will be necessary to understand the progression and outcomes of treatment options for these rare causes of IAC stenosis.
| Conclusion|| |
IACOs are rare, slowly growing, benign tumors. Currently, there is no consensus regarding whether or when to operate. Observation, including serial CT, is recommended for asymptomatic patients. Decisions regarding surgical interventions should be carefully considered depending on patient complaints, history of acoustic and vestibular symptoms, and the risk for occlusion of the IAC. Close clinical monitoring is needed to avoid unexpected complications. Future studies should be performed to monitor patients over time with serial imaging, radiography, and neurodiagnostic testing to elucidate the natural history of this condition.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]