• Users Online: 116
  • Print this page
  • Email this page


 
 
Table of Contents
CASE REPORT
Year : 2020  |  Volume : 22  |  Issue : 1  |  Page : 36-39

Internal auditory canal osteoma: Wait or operate – Case report and literature review


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 Submission02-Nov-2019
Date of Decision09-Dec-2019
Date of Acceptance07-Feb-2020
Date of Web Publication01-Jun-2020

Correspondence Address:
Dr. Abdulaziz AlEnazi
Department of Otorhinolaryngology.Head and Neck Surgery, Imam Abdul Rahman Bin Faisal University, King Fahd Hospital of the University, Alkhobar
Saudi Arabia
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/SJOH.SJOH_18_19

Rights and Permissions
  Abstract 


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 Top


Osteomas of the internal auditory canal (IAC) are rare and slowly progressive entities and uncommonly symptomatic.[1] It is most often located in the facial sinuses or cranial vault,[2] they are often clinically silent, lasting for years and may be diagnosed incidentally on a cerebral or facial computed tomography (CT) scan.[3] The most common symptoms include unilateral sensorineural hearing loss, vertigo and less commonly, tinnitus, due to direct pressure on the vestibulocochlear nerve.[4] Treatment options for IACOs are based mainly on symptom severity caused by nerve compression and to avoid irreversible complications.[5] Surgical options have been described in the few cases reported in the literature, in which clinical improvement ruled out the consideration of surgical intervention.[6] The site of these tumors should be considered because they are dangerous, and the risks for surgical complications are high.[7] Nevertheless, a review of surgical outcomes for IACOs in a case series by Davis et al. described some improvement and all symptoms resolved.[8] Surgical approaches depend on hearing level, location, and compression symptoms.[1],[9],[10] 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 Top


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

Click here to view
Figure 2: A coronal computed tomographic scan showing a right internal auditory canal osteoma

Click here to view
Figure 3: (a-c), Axial (d), coronal T2-weighted magnetic resonance imaging showing an osteoma in the right internal auditory canal

Click here to view
Figure 4: Sagittal T2-weighted magnetic resonance imaging, Rt internal auditory canal osteoma

Click here to view
Figure 5: (a) Pure-tone audiometry during the work up (b) Pure-tone audiometry during follow-up

Click here to view



  Discussion Top


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.[1],[2] Osteomas found in the IAC are rare.[3],[4],[5] 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.[6] In addition, osteoma can be asymptomatic, lasting for years and incidentally found on radiography.[1],[7],[8],[9] 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.[10],[11] 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.[12] 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.[13],[14] 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.[14] 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.

Literature review

IAC osteoma is a rare condition, and its natural history remains largely unknown. The treatment of IAC osteomas remains controversial.[1] 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.[15] 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.[8] 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.[10] 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 Top


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

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Gerganov VM, Samii A, Paterno V, Stan AC, Samii M. Bilateral osteomas arising from the internal auditory canal: Case report. Neurosurgery 2008;62:e528-9.  Back to cited text no. 1
    
2.
Liétin B, Bascoul A, Gabrillargues J, Crestani S, Avan P, Mom T, et al. Osteoma of the internal auditory canal. Eur Ann Otorhinolaryngol Head Neck Dis 2010;127:15-9.  Back to cited text no. 2
    
3.
Mirra JM. Osteoma in Bone Tumors: Clinical, Radiologic, and Pathologic Correlations. Philadelphia: Lea and Febiger; 1989. p. 174-82.  Back to cited text no. 3
    
4.
Clerico DM, Jahn AF, Fontanella S. Osteoma of the internal auditory canal. Case report and literature review. Ann Otol Rhinol Laryngol 1994;103:619-23.  Back to cited text no. 4
    
5.
Baik FM, Nguyen L, Doherty JK, Harris JP, Mafee MF, Nguyen QT. Comparative case series of exostoses and osteomas of the internal auditory canal. Ann Otol Rhinol Laryngol 2011;120:255-60.  Back to cited text no. 5
    
6.
Ramsay HA, Brackmann DE. Osteoma of the internal auditory canal. A case report. Arch Otolaryngol Head Neck Surg 1994;120:207-8.  Back to cited text no. 6
    
7.
Marsot-Dupuch K, et al. Imagerie Des Tumeurs De L'oreille. 2004; Available from: www.sciencedirect.com/science/article/abs/pii/S1762568804000466.  Back to cited text no. 7
    
8.
Davis TC, Thedinger BA, Greene GM. Osteomas of the internal auditory canal: A report of two cases. Am J Otol 2000;21:852-6.  Back to cited text no. 8
    
9.
Graham MD. Osteomas and exostoses of the external auditory canal. A clinical, histopathologic and scanning electron microscopic study. Ann Otol Rhinol Laryngol 1979;88:566-72.  Back to cited text no. 9
    
10.
Vrabec JT, Lambert PR, Chaljub G. Osteoma of the internal auditory canal. Arch Otolaryngol Head Neck Surg 2000;126:895-8.  Back to cited text no. 10
    
11.
Tamir SO, Cyna-Gorse F, Sterkers O. Internal auditory canal osteoma: Case report and review of the literature. Ear Nose Throat J 2015;94:e23-5.  Back to cited text no. 11
    
12.
Allen RW, Harnsberger HR, Shelton C, King B, Bell DA, Miller R, et al. Low-cost high-resolution fast spin-echo MR of acoustic schwannoma: An alternative to enhanced conventional spin-echo MR? AJNR Am J Neuroradiol 1996;17:1205-10.  Back to cited text no. 12
    
13.
Singh V, Annis JA, Todd GB. Osteoma of the internal auditory canal presenting with sudden unilateral hearing loss. J Laryngol Otol 1992;106:905-7.  Back to cited text no. 13
    
14.
Molher J, Pujol EMD, Zounon ADS, Darrouzet V, Bonnard D. Middle ear osteoma causing mixed hearing loss: A case report. J Int Adv Otol 2018;14:493-6.  Back to cited text no. 14
    
15.
Schutt CA, Guo JN, Bagwell KA, Bulsara KR, Malhotra A, Michaelides E. Bilateral osteomas and exostoses of the internal auditory canal. Am J Otolaryngol 2015;36:583-6.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Case Report
Discussion
Conclusion
References
Article Figures

 Article Access Statistics
    Viewed120    
    Printed4    
    Emailed0    
    PDF Downloaded27    
    Comments [Add]    

Recommend this journal