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Year : 2022  |  Volume : 28  |  Issue : 2  |  Page : 160-162

External ear canal osteoma presented as multilobulated mass with peripheral calcifications

1 Department of Otorhinolaryngology-Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia; Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine, Universiti Teknologi Mara, Selangor, Malaysia
2 Department of Otorhinolaryngology-Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia; Otorhinolaryngology-Head and Neck Surgery Specialist Clinic, Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia

Date of Submission30-Jul-2021
Date of Decision20-Sep-2021
Date of Acceptance19-Oct-2021
Date of Web Publication21-Sep-2022

Correspondence Address:
Dr. Mohd Khairi Md Daud
Department of Otorhinolaryngology-Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/indianjotol.indianjotol_119_21

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External auditory canal (EAC) osteoma is a slow-growing benign tumor. It appears as a single, pedunculated hyperdense lesion. Most osteomas are asymptomatic and treated conservatively while surgery is reserved for symptomatic osteomas. Surgical excision of EAC osteoma is approached either endoscopically or microscopically by postauricular, endaural, or transcanal approaches depending on the site and size of osteomas. We report a case of external auditory osteoma presented with an atypical finding of multilobulated mass with peripheral calcification on computed tomography scan.

Keywords: Canal, conductive hearing loss, external ear, osteoma

How to cite this article:
Kailani AA, Nik Othman NA, Md Daud MK. External ear canal osteoma presented as multilobulated mass with peripheral calcifications. Indian J Otol 2022;28:160-2

How to cite this URL:
Kailani AA, Nik Othman NA, Md Daud MK. External ear canal osteoma presented as multilobulated mass with peripheral calcifications. Indian J Otol [serial online] 2022 [cited 2022 Nov 27];28:160-2. Available from: https://www.indianjotol.org/text.asp?2022/28/2/160/356443

  Introduction Top

Osteoma is a benign, slow-growing osteogenic neoplasm. It may occur in any part of the temporal bone with the external auditory canal (EAC) being the most common site. EAC osteoma is commonly arises from tympanosquamous or tympanomastoid sutures beside the bony-cartilaginous junction. The etiology remains unknown. Clinically, it appears as a single, pedunculated lesion and usually affects one ear only. Symptoms may arise after many years when the lesion causes obstruction of the EAC. Classical findings of osteoma are single, pedunculated hyperdense lesion with an unchanged ear canal dimension.[1] We report a case of EAC osteoma presented with an atypical finding of multilobulated mass with peripheral calcification on computed tomography (CT) scan.

  Case Report Top

A 22-year-old male presented with reduced hearing of the left ear for 2 years duration which was gradually worsening. It was associated with ear discomfort, ear fullness, and buzzing tinnitus but does not affect his daily activities or sleep. He denied history of recurrent otorrhea, otalgia, cold water exposure, or trauma to the ear.

On examination, there was a hard, multilobulated mass occupying almost the whole part of the left EAC [Figure 1]. The posterior part of the tympanic membrane™ was slightly seen by otoendoscopy. Nevertheless, the ear canal was dry. The examination of the right ear showed no abnormality. The facial nerves were intact bilaterally. The nose, throat, and neck examinations were unremarkable. Pure tone audiogram demonstrated a mild-to-moderate conductive hearing loss on the left ear and normal hearing on the right ear.
Figure 1: Otoendoscopic view of the left external ear canal showing a multilobulated mass

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High-resolution CT (HRCT) of the temporal bone revealed a lobulated soft-tissue lesion with peripheral calcifications arising from the bony part of the left external ear canal measuring 0.5 cm × 1.1 cm × 0.5 cm [Figure 2]. It projected into lateral one-third of the left EAC without causing bony erosion. Otherwise, bilateral tympanic membranes, middle ear ossicles, cochlear, and semicircular canals were normal.
Figure 2: High-resolution computed tomography scan showing a soft-tissue lesion with peripheral calcifications

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Subsequently, he underwent endoscopic excision of the left ear canal mass by transcanal approach. Marcaine adrenaline was infiltrated around the lesion and base to reduce intraoperative bleeding. The mass originated from the posterosuperior part of the outer half of the canal. The skin flap lateral to the stalk was raised and the peduncle was fractured and removed. The remaining bony projection of the stalk was cleared using a high-speed drill [Figure 3]. The flap was then repositioned. [Figure 4] shows the mass that has been removed. The EAC was packed with gelfoam and chloramphenicol ointment to prevent infection. Postoperatively, no complications arose and his hearing and ear fullness markedly improved. The histopathological examination showed a bony lesion covered by benign stratified squamous epithelium with a central area composed of interconnecting trabecules of lamellar bone. The bone was lined by osteoblasts and the surrounding stroma was fibrous and well vascularized. No recurrence was noted after 6 months of follow-up.
Figure 3: Black arrow showing the intraoperative view of peduncle after removing the main bulk of the lesion

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Figure 4: The size of the mass as measured postoperatively

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  Discussion Top

Osteoma is a noninvasive osteogenic tumor that may arise from any compact or cancellous bone. It commonly arises from the anterior aspect of the bony-cartilaginous junction of the EAC.[2] Many theories had been proposed for EAC osteomas such as injury, recurrent inflammation, developmental disorders, hormones, and genetics.[3] EAC osteoma and exostosis have common overlapping symptoms such as hearing impairment, aural fullness, and otalgia. Both are usually asymptomatic for many years unless the EAC is obscured with concurrent infection or cholesteatoma causing obstruction of epithelial migration.

However, osteoma shows up as unilateral, single, pedunculated hyperdense lesion arising from tympanomastoid suture while exostosis appears as bilateral, multiple, broad-based mass with a regular border.[4] Interestingly, our case presented as a soft-tissue lesion with peripheral calcifications instead of a typical hyperdense lesion on HRCT. Histologically, osteoma can be categorized into compact or ivory, cancellous, and mixed-type osteomas.[5] The compact osteoma has a sessile base and consists of dense bone with little marrow spaces.[6] Meanwhile, the cancellous osteoma is typically pedunculated and appears like the original bone.[6] It contains bony trabeculae and fibro-fatty marrow encircled by osteoblasts, which is similar to our case.

Classically, EAC osteomas are removed microscopically through transcanal, postauricular, and endaural approaches. A small pedunculated lesion located lateral to the isthmus can be removed directly through transcanal while the other approaches are recommended for a big broad base lesion located more medially. Recently, quite a number of surgeons have shifted to transcanal endoscopic ear surgery. Chen et al. published a case series regarding the outcomes of endoscopic management of EAC osteoma using two methods of direct removal with and without skin flap.[7] Osteoma in our case was removed by elevation of the skin flap near the base followed by drilling of the peduncle for complete removal. We recommend raising a skin flap even for small stalk before drilling or curetting to ensure complete removal of the base. This is also to prevent injury to healthy EAC skin. Directly curetting or drilling the stalk base without skin flap has a higher tendency for injury and risk of incomplete excision, hence promoting recurrence.

The endoscopic approach of EAC osteoma has a few advantages compared to the microscopic approach. It is proven to reduce operating time, provide a wide surgical field and preserve the skin by avoiding postauricular or endaural incision.[8] Some limitations such as one-hand surgery and limited space for instruments are trivial as drilling is also possible with one hand to control drilling pressure. Precautions are taken while drilling the anterior EAC and the posterior wall due to the relations to two important structures which are the temporomandibular joint and the facial nerve, respectively.

  Conclusion Top

External auditory osteoma should be considered a differential diagnosis in a case of multilobulated mass in EAC. It may appears as a lobulated soft-tissue lesion with peripheral calcifications on HRCT of the temporal bone.

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.

  References Top

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. 1
Tran LP, Grundfast KM, Selesnick SH. Benign lesions of the external auditory canal. Otolaryngol Clin North Am 1996;29:807-25.  Back to cited text no. 2
Barbon DA, Hegde R, Li S, Abdelbaki A, Bajaj D. Bilateral external auditory exostoses causing conductive hearing loss: A case report and literature review of the surfer's ear. Cureus 2017;9:e1810.  Back to cited text no. 3
Viswanatha B. A case of osteoma with cholesteatoma of the external auditory canal and cerebellar abscess. Int J Pediatr Otorhinolaryngol Extra 2007;2:34-9.  Back to cited text no. 4
de França TR, Gueiros LA, de Castro JF, Catunda I, Leão JC, da Cruz Perez DE. Solitary peripheral osteomas of the jaws. Imaging Sci Dent 2012;42:99-103.  Back to cited text no. 5
Sayan NB, Uçok C, Karasu HA, Günhan O. Peripheral osteoma of the oral and maxillofacial region: A study of 35 new cases. J Oral Maxillofac Surg 2002;60:1299-301.  Back to cited text no. 6
Chen CK, Chang KP, Chien CY, Hsieh LC. Endoscopic transcanal removal of external auditory canal osteomas. Biomed J 2021;44:489-94.  Back to cited text no. 7
Marchioni D, Alicandri-Ciufelli M, Mattioli F, Nogeira JF, Tarabichi M, Villari D, et al. From external to internal auditory canal: Surgical anatomy by an exclusive endoscopic approach. Eur Arch Otorhinolaryngol 2013;270:1267-75.  Back to cited text no. 8


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


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