Journal of Oral and Maxillofacial Radiology

: 2016  |  Volume : 4  |  Issue : 2  |  Page : 40--43

Idiopathic antral exostoses: Two rare cases in maxillary sinus

Gulsun Akay1, Oguzhan Demirel2, Ilkay Peker1, Kahraman Gungor1, Meryem Toraman Alkurt1, Ozlem Ucok1,  
1 Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Gazi University, Ankara, Turkey
2 Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Istanbul Medipol University, Istanbul, Turkey

Correspondence Address:
Gulsun Akay
Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Gazi University, Emek, Çankaya, Ankara


During routine panoramic radiographic examinations, a series of incidental findings may be observed in maxillary sinuses. One of these findings may be exostoses which are the outgrowths of compact and cancellous bone. In this case report, we represent two cases of exostosis of the maxillary sinus evaluated using cone-beam computed tomography. Although antral exostoses have no clinical importance, except if they cause obstruction of sinus ostium, their differential diagnosis must be achieved from other pathologies with similar radiographic properties such as anthroliths and osteomas.

How to cite this article:
Akay G, Demirel O, Peker I, Gungor K, Alkurt MT, Ucok O. Idiopathic antral exostoses: Two rare cases in maxillary sinus.J Oral Maxillofac Radiol 2016;4:40-43

How to cite this URL:
Akay G, Demirel O, Peker I, Gungor K, Alkurt MT, Ucok O. Idiopathic antral exostoses: Two rare cases in maxillary sinus. J Oral Maxillofac Radiol [serial online] 2016 [cited 2020 Jul 5 ];4:40-43
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Exostoses are the outgrowths of normal compact and cancellous bone, and they may be seen in different locations of the jaws. Maxillary and mandibular tori and dense bone islands are the most common and well-known exostoses in dentistry. Similarly, external auditory canal exostoses are widely examined in otolaryngology literature. Currently, several authors are interested in antral exostoses. Although this entity has been firstly reported in 2010 by Ramakrishnan et al. [1] in otolaryngology literature; in fact, Ohba et al. [2] previously investigated the prevalence of antral exostoses in panoramic radiographs and they reported as 0.9% in the dental literature. However, this relatively new diagnostic entity has been disregarded by the investigators to date 2010 and then the subject attracted attention of dentists and otolaryngologists. There is no clinical importance of antral exostoses; however, the differential diagnosis should be made from pathologies such as anthroliths and osteomas located in the maxillary sinuses to avoid the unnecessary surgical procedures. [2]

Panoramic radiography is the basic imaging modality for the diagnosis of dental and maxillofacial pathologies. This technique allows visualization of maxillary sinuses and incidental findings including mucosal changes, anthroliths, retained root tips, and exostoses are discovered during routine radiologic examinations [2] Cone-beam computed tomography (CBCT) is a three-dimensional radiographic technique which can be used to assess the maxillary sinus pathologies and anatomy. [3],[4]

There are few reports regarding antral exostoses in both dentistry and otolaryngology literature. [1],[5],[6],[7],[8] In this case report, we represented two patients attended to our clinic for dental complaints and diagnosed as having maxillary sinus exostoses during panoramic radiographic examination and underwent CBCT evaluation.

 Case Reports

Case 1

Twenty-year-old female patient attended to our clinic for the examination of impacted third molar teeth. Panoramic radiography revealed oval and amorphous radiopacities adjacent to the root tips of the first and second molar teeth inside the left and right maxillary sinuses [Figure 1]. Then, the patient was referred for the CBCT examination to determine the localization and structure of the lesions. Five bony exostoses; two in the right and three in the left maxillary sinuses were detected in CBCT scans. One of the exostoses in the right maxillary sinus was in the inferior wall and round shaped [Figure 2], and the other was localized in the inferolateral wall and sharp-edged in shape [Figure 3]. Two of the exostoses were in the inferior wall of the left maxillary sinus, and one of them was sharp-edged and the other one was round in shape [Figure 4] and [Figure 5]. One exostosis was in the posteroinferior wall of the maxillary sinus and was round in shape [Figure 6]. All of the structures showed continuity along the sinus wall and were diagnosed as bilateral maxillary sinus exostoses. The largest exostosis in the right sinus showed 5.6 mm Χ 6.4 mm Χ 8 mm and in the left sinus 6.8 mm Χ 7.2 mm Χ 6.4 mm dimensions. Patient history revealed no sinus complaints and sinonasal treatment of any kind.{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}

Case 2

Forty-nine-year-old female patient attended to our clinic because of prosthetic complaints. The patient reported no sinus complaints or sign of sinus inflammation and any kind of sinonasal treatment. However, she performed nasal irrigation with tap water in five times a day for 20 years because of wudu; the Islamic act of washing parts of the body using water. Panoramic radiograph was taken for dental examination. Pedunculated bony structures were detected in the inferior wall of the left maxillary sinus [Figure 7], and the patient was referred for CBCT evaluation. Unilateral pedunculated exostosis including cancellous and compact bone was found originating from the inferolateral wall of the left maxillary sinus and was showing continuity along the sinus wall [Figure 8]. The size of the lesion was 3.6 mm Χ 6.8 mm Χ 11.6 mm. We advised the patient to use water at room temperature during wudu.{Figure 7}{Figure 8}


Some alterations and lesions can be found during routine panoramic radiographic examinations including hypoplasia or aplasia of the maxillary sinuses, presence of septa, overpneumatization of the maxillary sinus, tumors and tumor-like lesions, anthroliths, foreign bodies, and exostoses. [2],[9],[10] Antral exostoses are rare bone hyperplasias, and their prevalence has been reported as 0.9% [2] and 2.6% [10] in only two studies in the literature.

Adequate radiographic examination of maxillary sinuses is important in dental practice. Panoramic radiography is a radiographic technique in which all the teeth and jaw structures can be viewed at one scan, and it is routinely used for dental examinations. Maxillary sinuses are in the imaging field of panoramic radiography, and some incidental findings and pathologies can be detected during radiographic examinations. [9] Although some studies [2],[9] showed that panoramic radiography is a reliable method for the assessment of maxillary sinuses, superimpositions of the cranial structures may negatively affect diagnostic accuracy of the maxillary sinus examinations. CBCT is a helpful diagnostic tool to identify anatomical variations and maxillary sinus abnormalities without superimpositions. [9] In this report, antral exostoses were initially observed on panoramic radiographs and CBCT examinations were obtained in both of the cases to determine accurate localizations.

Some authors advocate that there is a possible correlation between cold temperatured nasal irrigation, cold-water swimming, and antral exostoses. [5],[6] According to our knowledge, there are seven published cases regarding antral exostoses. The majority of previous published cases (n = 6, 85.7%) in literature are related with a long history of cold temperatured nasal irrigation, cold-water swimming, sinusitis, and maxillary sinus surgery [6],[7],[8] with symptoms including discomfort, pain, and inflammation. There were no symptoms in reported cases except for one (n = 1, 14.3%). [8] In present cases, exostoses were found in routine radiographic examination, and the patients did not report any complaint on the contrary as reported by Borie et al. [8] In second case, the patient performed nasal irrigation with tap water five times a day for 20 years. This action may be considered as nasal irrigation although it was not performed with cold-water. In the published cases, it was reported that the patients kept the nasal irrigants in refrigerator. [1],[5],[6]

Antral exostoses have been found generally as unilateral. Lana et al.'s [10] study including 500 CBCT scans concluded with 13 cases of antral exostosis, and only two of them were bilateral. [10] There is only one case report in the literature demonstrated bilateral exostoses of the maxillary sinuses. [8] In our case report, the exostoses were observed unilaterally in one patient, and the other was bilateral. Ohba et al. found the average size of these lesions 4.7 mm Χ 7.4 mm and his measurements were on panoramic radiographs. [2] Borie et al.'s case report defined the size of these lesions as 6.3 mm Χ 9.8 mm in the right and 15.4 mm Χ 9.4 mm in the left sinus. [8] Our first case showed multiple bilateral exostoses, the largest in the right sinus was 5.6 mm Χ 6.4 mm Χ 8 mm and 6.8 mm Χ 7.2 mm Χ 6.4 mm in the left sinus. The second case was unilateral and 3.6 mm Χ 6.8 mm Χ 11.6 mm in size. Some authors reported that 55% of exostosis were located on the posterior wall and floor of the maxillary sinus and 10% with boundary of medial and anterior walls. [2] In our cases, all the lesions were located in the inferior wall.

Antral exostoses generally do not require surgical approaches due to biopsy is not usually suggested unless they do not cause any clinical symptoms and lead to sinonasal obstruction. The otolaryngologists advise to irrigate with solutions at room temperature for the patients with long history of nasal irrigation. [5],[6] However, biopsy could be useful in some cases with an inconsistent history or noncharacteristic-appearing lesions. [5] No treatment was performed, and periodic dental examinations were decided for our patients. Furthermore, we advised the second case to use water at room temperature during wudu.


The present cases are considerably rare within previous published cases because there was no complaint for both cases and no history of previously reported-related factors in the first case. In second case, the possible reason may be nasal irrigation with tap water five times a day for 20 years during wudu, the Islamic act of washing parts of the body with water. There was no history of maxillary sinus surgery in both of the cases. In addition, the lesions were observed bilaterally in this report, and this finding is relatively rare. The detection of exostoses in the maxillary sinus seems to be suitable with CBCT scan. Although antral exostoses are rare conditions, their differential diagnosis should be carried out from other pathologies to avoid the unnecessary surgical procedures. Clinicians should be aware of the reasons, radiographic findings, and possible complications of antral exostoses.

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Conflicts of interest

There are no conflicts of interest.


1Ramakrishnan JB, Pirron JA, Perepletchikov A, Ferguson BJ. Exostoses of the paranasal sinuses. Laryngoscope 2010;120:2532-4.
2Ohba T, Langlias RP, Langland OE. Antral exostosis in panoramic radiographs. Oral Surg Oral Med Oral Pathol 1993;76:530-3.
3Rege IC, Sousa TO, Leles CR, Mendonça EF. Occurrence of maxillary sinus abnormalities detected by cone beam CT in asymptomatic patients. Biomed Cent Oral Health 2012;12:1-7.
4Ritter L, Lutz J, Neugebauer J, Scheer M, Dreiseidler T, Zinser MJ, et al. Prevalence of pathologic findings in the maxillary sinus in cone-beam computerized tomography. Oral Surg Oral Med Oral Radiol Endod 2011;111:634-40.
5Haffey T, Woodard T, Sindwani R. Paranasal sinus exostoses: An unusual complication of topical drug delivery using cold nasal irrigations. Laryngoscope 2012;122:1893-7.
6Adelson RT, Kennedy DW. Paranasal sinus exostoses: Possible correlation with cold temperature nasal irrigation after endoscopic sinus surgery. Laryngoscope 2013;123:24-7.
7Schwartz KM, Eckel LJ, Black DF, Lehman VT, Diehn FE, Hunt CH, et al. Irrigation nose: CT findings of paranasal sinus exostoses. Open Neuroimag J 2012;6:90-1.
8Borie E, Watanabe PC, Orsi IA, Fuentes R. Idiopathic bilateral antral exostoses: A rare case in maxillary sinus. Int J Surg Case Rep 2014;5:624-7.
9Mathew AL, Pai KM, Sholapurkar AA. Maxillary sinus findings in the elderly: A panoramic radiographic study. J Contemp Dent Pract 2009;10:E041-8.
10Lana JP, Carneiro PM, Machado Vde C, de Souza PE, Manzi FR, Horta MC. Anatomic variations and lesions of the maxillary sinus detected in cone beam computed tomography for dental implants. Clin Oral Implants Res 2012;23:1398-403.