|Year : 2013 | Volume
| Issue : 1 | Page : 58-60
Solitary osteoma of body of the mandible
Saba Khan1, Laxmikanth Chatra2, K Prashanth Shenai2, Sreeja P Kumar3
1 Department of Oral Medicine and Radiology, NIMS Dental College and Hospital, NIMS University, Jaipur, Rajasthan, India
2 Department of Oral Medicine and Radiology, Yenepoya Dental College and Hospital, Derelakatte, Mangalore, Karnataka, India
3 Department of Oral Medicine and Radiology, KMCT Dental College, Mukkum, Calicut, Kerela, India
|Date of Web Publication||20-Jun-2013|
Department of Oral Medicine and Radiology, NIMS Dental College and Hospital, NIMS University, Shobha Nagar, Jaipur-Delhi Highway, Jaipur - 303 121, Rajasthan
Source of Support: None, Conflict of Interest: None
Osteomas are relatively rare benign osteogenic neoplasm's characterized by the proliferation of compact or cancellous bone. Osteomas can develop as peripheral (periosteal) masses attached to the cortical plates or as central lesions arising from endosteal bone surfaces. Although multiple osteomas of the jaws are a hallmark of Gardner's syndrome (familial adenomatous polyposis), non-syndromic cases are typically solitary. The purpose of this paper is to present a large peripheral osteoma originating from the buccal surface of the mandible and causing asymmetry in a 35-year-old woman.
Keywords: Gardner′s syndrome, mandible, osteoma, pathology
|How to cite this article:|
Khan S, Chatra L, Shenai K P, Kumar SP. Solitary osteoma of body of the mandible. J Orofac Sci 2013;5:58-60
| Introduction|| |
Osteomas are benign lesions composed of mature compact or cancellous bone that grow continuously. It has been variously considered to be a neoplasm, a developmental or reactive osteogenic lesion resulting from muscle traction on the periosteum or due to trauma. Osteomas of the jaws may arise on the surface of the bone as a polypoid or sessile mass (periosteal osteoma), in the medullary bone (endosteal osteoma) or in the softtissue (extra skeletal osteoma). The most common location of the periosteal osteoma is the skull. However, lesions also rarely occur in the mandible, especially on the lingual aspect of the, angle, inferior border and body as seen in the present case. 
| Case Report|| |
A 35 year-old female patient came to the dental out patient department with the chief complaint of swelling over the left lower jaw region since 6 months. She gave the history that the swelling was first noticed 6 months back, insidious in onset, gradually increased to the present size and thereafter no fluctuation in the size of swelling was noticed. The swelling was not associated with pain, discharge, fever, paresthesia or difficulty in eating or speaking. No history of trauma, infection or history of similar swelling in that region. Salivary flow was normal. No similar swellings elsewhere in the body. The patient was in apparent good health and her medical history was noncontributory.
On extra oral examination a solitary diffuse swelling was seen in respect to the left lower border of the mandible extending anterioposteriorly from the line drawn from the left angle of the mouth to 3 cm short of the left ear lobe. Superioinferiorly it is confined to the buccal aspect and the lower border of the mandible. The surface appeared smooth and not stretched with no signs of erythema. The color and texture appeared same as that of adjacent skin. The margins were regular, diffused and continuous with adjacent mucosa. No ulcer, sinus, discharge were evident [Figure 1].
|Figure 1: Solitary diffuse swelling seen in left inferior border of the mandible|
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On palpation of the site size and extent of the lesions were confirmed. Swelling was non-tender, bony hard in consistency extending up to 0.5 cm above the buccal aspect extending below the lower border of the mandible and also involving the medial aspect of the mandible. The superficial skin over the swelling was pinchable. There was no change in the texture and no local rise in the temperature evident. The swelling was non-compressible, non-reducible, non-fluctuant, non-pulsatile. It was sessile and fixed to the underlying bone with only the overlying skin adhered over it. Expansion of the medial cortex was evident on palpation, however, crepitus was absent.
On intraoral examination, inspectory findings revealed missing 36. Overlying mucosa in respect to the edentulous 36 region appeared normal. On palpation the regional teeth were not mobile, decayed or tender on percussion, no cortical bone expansion or vestibular space obliteration was evident [Figure 2].
Hence based on the history given by the patient and the clinical examination carried out, a provisional diagnosis of peripheral osteoma (PO) was given. For differential diagnosis periosteal reaction, exostosis and Garre's osteomyelitis were considered.
|Figure 2: No cortical bone expansion or vestibular space obliteration evident|
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Computed tomography was done and the axial sections at the level of the first vertebrae showed a nodular well defined, homogeneous radio opaque mass arising from the periosteum in respect to the left buccal cortex and lower border of the mandible on the buccal aspect adjacent to 37 region [Figure 3] and [Figure 4]. The 3D reconstruction of the computed tomography image revealed a pedunculated homogeneous bony mass attached to the buccal cortex at the body of the mandible [Figure 5]. A final diagnosis of PO of the left lower mandible was made. Treatment planned for the patient was complete resection of the lesion. Since the patient was not willing for surgery, she was kept on a 6 months follow-up. The lesion did not show any change until 2 years of follow-up.
|Figure 3: Homogeneous radio opaque mass arising from the periosteum in respect to the left buccal cortex and lower border of the mandible in the axial section|
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|Figure 4: Homogeneous radio opaque mass arising from the periosteum in respect to the left buccal cortex and lower border of the mandible in coronal section|
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|Figure 5: 3D reconstruction of the computed tomography image revealed a pedunculated homogeneous bony mass attached to the buccal cortex|
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| Discussion|| |
It has been reported that osteomas are often noted in the sixth decade, but reports range from 16 years to 74 years of age. Males and females were equally affected.  Children are almost never affected unless they have Gardner's syndrome, which is an autosomal dominant trait that features osteomas, fibromatosis of the skin and fascia, and polyposis of large intestine with a high degree of malignant transformation. Osteomas are found mainly in the craniofacial bones. POs are more frequent in the mandible than in the maxilla. A PO occurs most frequently in the paranasal sinuses, the most common site being the frontal sinus followed by the maxillary sinus. Other locations include the orbital wall, temporal bone, pterygoid processes and external ear canal.  The most frequent sites affected in the mandible are the posterior body followed by the condyle, angle, ascending ramus, coronoid process, anterior body and sigmoid notch.
The pathogenesis of osteomas is not completely known. They are referred to developmental anomalies, true neoplasms or reactive lesions triggered by trauma, muscle traction, or infection.  Infiltration of interdental bone and abnormal histological bone structure might support the neoplastic nature of this lesion. 
POs are slow-growing lesions and clinically they usually remain asymptomatic, unless it develops within the medullary space. However, POs may expand to the extent that they cause facial asymmetry and functional impairment. Mostly they are unilateral, pedunculated, mushroom-like masses with freely mobile overlying mucosa.  As seen in the present case, the origin of the osteoma could be peripheral, as it appeared as a lobulated mass at the buccal cortex of the mandible. 
Histologically osteomas consist of mature, lamellar bone or cancellous bone with abundant fibro fatty marrow between bony trabeculae as reported in our case. Histologically there is no evidence of differentiation between osteoma, osteochondroma, and tori it can only be differentiated clinically and radiographically. 
Radiographically osteomas show a well circumscribed, densely sclerotic and radiopaque mass.  PO should be differentiated from several pathologic entities such as exostoses, osteoblastoma, osteoid osteoma, late-stage central ossifying fibroma or complex odontoma. Exostoses are bony excrescences that usually stop growing after puberty, differentiating them from osteomas. The borders of central ossifying fibromas are well-defined and a thin radiolucent line may separate it from the surrounding bone. Osteoblastomas and osteoid osteomas are more frequently painful and grow more rapidly than POs. A complex odontoma presents as a well-defined radiopacity situated in bone, but with a density that is greater than bone and equal to or greater than that of a tooth. It is also surrounded by a narrow radiolucent rim. 
Recurrence of PO after surgical excision is extremely rare and the goal of the follow-up is to lookout for new osteomas or other signs indicative of Gardner's syndrome, which was ruled out in our case. Malignant transformation of PO has not been reported in the literature.
| Conclusion|| |
Osteomas are slow growing benign tumours with a very rare recurrence rate.
Radiographic follow-up on a 6 month schedule is recommended for 2-3 years, with two additional annual radiographs thereafter. 
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]