|Year : 2014 | Volume
| Issue : 1 | Page : 35-37
Peripheral osteoma of the mandible with radiologic and histopathologic findings
Asli Tanrivermis Sayit1, Gokhan Kutlar2, Ilkay Sedakat Idilman3, Pinar Hediye Gunbey4, Asuman Celik5
1 Department of Radiology, Samsun Gazi State Hospital, Samsun, Turkey
2 Department of Otorhinolaryngology, Samsun Gazi State Hospital, Samsun, Turkey
3 Department of Radiology, Ankara Ataturk Education and Research Hospital, Ankara, Turkey
4 Department of Radiology, Samsun Education and Research Hospital, Samsun, Turkey
5 Department of Pathology, Samsun Gazi State Hospital, Samsun, Turkey
|Date of Web Publication||2-Jun-2014|
Asli Tanrivermis Sayit
Department of Radiology, Samsun Gazi State Hospital, Samsun
Source of Support: None, Conflict of Interest: None
Clinical trial registration jomr_3_14
Osteomas are benign, slow growing osteogenic tumors. They are often occurring in the craniofacial bones but rarely originates from the mandible. Osteomas have three varieties as central, peripheral and extraskeletal. Central and peripheral osteomas are often seen in the facial bones. Peripheral osteoma often located in the frontal, ethmoid and maxillary sinus, but rarely occurs in the jaws. Usually they are asymptomatic and discovered incidentally during radiological and clinical examinations. Osteomas are characterized with well-defined, rounded or oval radiopaque mass in the computed tomography. Herein, we report a rare case of peripheral osteoma of the lower part of the mandible in a 19-year-old female with radiologic and pathologic findings.
Keywords: Computed tomography, mandible, osteoma
|How to cite this article:|
Sayit AT, Kutlar G, Idilman IS, Gunbey PH, Celik A. Peripheral osteoma of the mandible with radiologic and histopathologic findings. J Oral Maxillofac Radiol 2014;2:35-7
|How to cite this URL:|
Sayit AT, Kutlar G, Idilman IS, Gunbey PH, Celik A. Peripheral osteoma of the mandible with radiologic and histopathologic findings. J Oral Maxillofac Radiol [serial online] 2014 [cited 2020 Apr 5];2:35-7. Available from: http://www.joomr.org/text.asp?2014/2/1/35/133570
| Introduction|| |
Osteomas of facial bones are benign osteogenic tumors characterized by the proliferation of compact or cancellous bone. They originate from the craniomaxillofacial region such as temporal bones, sinuses or jaws. They usually occur between 2 nd and 5 th decade; however, may be seen at any age. There are three subtypes of osteomas; peripheral (parosteal, periosteal or exophytic), central (endosteal) and extraskeletal (osseous choristoma) osteoma. , Peripheral osteoma arises centrifugally from the periosteum; however, central osteoma arises centripetally from the endosteum. Extraskeletal soft tissue osteoma often originates from muscle tissue.  Peripheral osteoma is a rare entity and most frequently arises from paranasal sinuses. The less often sites that a peripheral osteoma may arise from are orbital wall, temporal bone, pterygoid process and external ear canal.  The prevalence of peripheral osteoma at jaw bones is quite rare and if occurs, lesions are most commonly seen at the mandible.  The purpose of this case report is to present a solitary peripheral mandibular osteoma with radiographic findings and to discuss differential diagnosis with relevant literature.
| Case Report|| |
The case we present here is a 19-year-old female patient who was referred to our clinic with a complaint of 3 monthly painless swelling on the right side of her face. On physical examination, non-pulsatile, non-tender, approximately 1 cm sized, hard mass was palpated at the buccal surface of the mandible. The overlying mucosa of the mass was normal in color and was not attached to the underlying mass. There was no prior history of facial trauma. A solitary, well-defined, round, 11 mm × 10 mm sized hyperdense lesion at the lower border of the body of the mandible was detected with computed tomography (CT) [Figure 1]. The mass had a similar density to the adjacent bone structure. On the basis of physical and radiographic examination, osteoma of the mandible was considered as initial diagnosis. Excision was performed under local anesthesia with extraoral approach and the mass was excised with a chisel and mallet. The marginal mandibular branch of the facial nerve was preserved during surgery. Macroscopically, yellowish solid mass of about 1 cm in diameter was visualized [Figure 2]. Patient was discharged without any complications. The histopathological study findings were consistent with osteoma [Figure 3].
|Figure 1: (a-c) Serial of the axial computed tomography images show that well-defined, rounded, radiopaque mass (arrow) attached to the right buccal surface of the lower border of the body of the mandible. Also, there is no cortical bone destruction or any abnormality in the surrounding tissues|
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|Figure 2: Well-defined, yellowish solid mass was observed with macroscopically|
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|Figure 3: Histopathological features of the mandibular osteoma consisting of osteoid cells (arrow) and haversian canal (H and E, × 100)|
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| Discussion|| |
Peripheral osteoma is a rare entity which is usually a pedunculated mushroom-like mass originating from the periosteum.  Etiology of this lesion is still unknown. Some investigators thought that it may be a true neoplasm or a developmental anomaly.  Furthermore, Kaplan et al. suggested that it may be a reactive lesion secondary to trauma, infection or muscle traction.  Close location of most of the peripheral osteomas with muscles such as masseter, medial pterygoid and temporalis muscle suggests an etiology secondary to muscle traction.  Most peripheral osteomas originate from the mandible body, angle, condyle and coronoid process. ,, It is usually located at the lower border or buccal aspect of the mandible which is more prone to trauma. They are usually asymptomatic; if symptomatic, symptoms vary depending on the size and location. Peripheral osteoma may cause facial deformity, headache, exophthalmos, mandible deviation. 
The suspicion for Gardner syndrome rises with a facial osteoma detection. Gardner syndrome may present with rectal bleeding, diarrhea and abdominal pain and characterized with colorectal polyposis, multiple osteoma, skin and soft tissue tumors, multiple impacted or supernumerary teeth.  Patients with colorectal poliposis with accompanying osteoma should be evaluated for Gardner syndrome as the intestinal polyps in Gardner syndrome are predominantly adenoma and the risk for malign progression is 100%.  Therefore, patients with colorectal polyposis and facial osteoma should be evaluated with colonoscopy and colorectal carcinoma must be excluded as early evaluation may improve prognosis of these patients. In our case, Gardner syndrome was not considered due to the absence of accompanying lesions.
Osteomas are usually discovered incidentally at radiological examinations. If they become symptomatic, diagnosis can be made with physical examination and radiological imaging. Panoramic radiography and CT can be used for the imaging.  But, CT is very useful for detection of the location and extension of the mass and also guidance for surgery. On CT images, peripheral osteomas are well-demarcated, round or oval mushroom-like hyperdense masses. Sessile lesions are often attached to the cortex with a broad base, whereas, pedunculated lesions have a thin contact area with compact bone.  In our case, well-defined, rounded, hyperdense solitary mass at the lower border of the body of the mandible was detected with CT. Lesion density was similar to the adjacent bone density, so it was primarily thought to be an osteoma.
Exostoses, osteoblastoma, osteoid osteoma, ossifying fibroma, late-stage central ossifying fibroma or complex odontoma should be considered in the differential diagnosis.  Exostoses are an extension of bone and usually stop growing after puberty. Ossifying fibroma is a well-defined mass with marginal sclerosis and a thin cortex. Bone expansion may be seen at 50% of cases. Aggressive lesions may have a characteristic ground-glass appearance.  Osteoblastoma and osteoid osteoma are painful lesions that tend to grow very fast. Benign osteoblastoma may cause expansion in the cortex of the mandible. It is an osteoblastic tumor and characterized with radiopaque and radiolucent patterns, depending on the degree of calcification. , Osteoblastoma arises from the medullary bone whereas osteoid osteoma arises from the cortical bone. Complex odontoma is a well-defined radiopacity, which is denser than the adjacent bone tissue. Furthermore narrow radiolucent rim can be seen around the mass. 
The surgical removal of asymptomatic peripheral osteoma is not generally necessary. Asymptomatic, small, non-progressing soliter osteomas can be just followed-up with physical and radiological examinations. However, surgical removal is indicated only large, deforming and progresif osteomas to cause facial asymmetry or functional malfunction.  Extraoral approach is preferred for larger tumors that located posterior of the mandible. Recurrence after resection is very rare and malignant transformation has not been reported in the literature.  In our case, extraoral approach was preferred due to the location of the lesion. The marginal mandibular branch of the facial nerve was preserved during surgery. Surgical intervention was completed without any complications.
| Conclusion|| |
We presented radiological findings of an osteoma on the buccal surface of the body of the mandible with literature review. As shown in our report, CT is a very useful modality for both detection of location and extension of osteomas. Furthermore, osteomas of the facial skeleton may be associated with Gardner's syndrome. Therefore, patients with osteoma of the facial skeleton should be evaluated for the colorectal carcinoma because early and advanced evaluation is very significant for the prognosis of the patient.
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[Figure 1], [Figure 2], [Figure 3]