CASE REPORT

Oral Radiol (2008) 24:39–41 © Japanese Society for Oral and Maxillofacial Radiology and Springer 2008DOI 10.1007/s11282-007-0067-x

Amit Mittal · Nageshwar Iyer

Large peripheral osteoma of the mandible

Abstract This case report concerns a 30-year-old man who presented with a large mass on the left side of the jaw in the submandibular area. Panoramic radiography and com-puted tomography revealed the swelling to be a peripheral osteoma of the mandible, which was excised surgically.

Key words Peripheral osteoma · Mandible · Panoramic radiography · Computed tomography

Introduction

An osteoma is a benign neoplasm of bone tissue character-ized by very slow, continuous growth. While both central and peripheral osteomas have been described in the facial bones, a peripheral osteoma of the mandible is uncommon. It is a circumscribed, slow-growing, generally asymptom-atic, hard mass producing obvious asymmetry.1 Here, we present a case of giant peripheral osteoma of the mandible with its radiological features.

Case report

A 35-year-old man came to the Department of Oral and Maxillofacial Surgery with a large swelling in the left sub-mandibular area leading to facial asymmetry, which had developed over the previous 5 years. The swelling was not painful, and no history of abdominal pain, rectal bleeding, diarrhea, or trauma was reported.

On examination, a large, nonmobile, bony, hard swelling measuring 4.0 cm × 4.1 cm × 4.0 cm in the left submandibular

A. Mittal (*)Department of Radiodiagnosis, MM Institute of Medical Sciences and Research, Mullana, Ambala District, Pin-133203 Haryana, IndiaTel. + 91-9416077793; Fax +91-1731-289732e-mail: amitmittalrad@yahoo.co.in

N. IyerDepartment of Oral and Maxillofacial Surgery, MM Institute of Dental Sciences and Research, Mullana, Ambala, India

area and angle of the mandible along the lower border of the mandible was detected. The overlying skin was normal, with no evidence of ulceration (Fig. 1). Swelling was also seen intraorally with intact overlying mucosa.

The patient was sent for a radiological examination. A panoramic radiograph (Fig. 2) showed a large lobulated radiodense mass in the left mandibular area that appeared to involve the roots of the posterior mandibular tooth. The tooth was found to be vital on pulp testing. These fi ndings were suggestive of endosteal osteoma or another calcifi ed odontogenic tumor affecting the jawbone requiring seg-mental or block resection.

As no migration of the inferior alveolar neurovascular canal or roots of the teeth was observed, computed tomog-raphy (CT) was performed to further evaluate the character and extent of the mass. CT was carried out on a Spiral CT scanner (Somatom; Siemens, Erlangen, Germany) in the axial and coronal planes, and a three-dimensional (3-D) reconstruction was made. CT showed a large, lobulated, well-defi ned radiopaque mass of bone density attached to the inferior part on the left side of the body of the mandible and extending along both the lingual and lateral borders, that is, intraorally and extraorally (Figs. 3 and 4). The mass did not involve the teeth or alveolus of the mandible; on panoramic radiograph, the mass only overlapped the teeth and alveolar area. The mandibular condyles and temporo-mandibular joints were normal. The mass was seen clearly in the shaded surface display reconstructions (Figs. 5 and 6).

On the basis of the CT fi ndings, a diagnosis of a large peripheral osteoma of the mandible was made. In this case, CT helped to differentiate the mass from an endosteal osteoma or calcifi ed odontogenic tumor, both of which require segmental or block resection with reconstruction. However, CT very clearly indicated that the mass had no relation to the teeth or alveolus of the mandible, and the fi ndings were diagnostic of a peripheral osteoma that required simple excision only, without the need for recon-struction. Without the aid of CT, the surgeon might plan an intraoral resection of this mass and discover a large lin-gually placed tumor mass, complicating the surgery. The CT

Received: August 20, 2007 / Accepted: October 12, 2007

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Fig. 1. Clinical photograph showing a large swelling on the left side of the face along the inferior border of the mandible

Fig. 2. Panoramic radiograph showing a lobulated radiodense mass along the left side of the body of the mandible near the periapical area of the lower left fi rst molar

Fig. 3. Axial computed tomography (CT) scan showing a lobulated bony mass arising from the inferior border of the body of the mandible

Fig. 4. Coronal CT showing a lobulated bony mass arising from the mandible with a wide base and both intraoral and extraoral components

Fig. 5. Shaded surface display reconstruction image showing a lobu-lated bony mass along the left side of the inferior border of the body of the mandible (front view)

Fig. 6. Shaded surface display reconstruction image showing a lobu-lated bony mass along the left side of the inferior border of the body of the mandible (side view)

scan helped with the planning of extraoral surgery, which turned out to be quite simple.

The swelling was excised, and a hard bony mass measur-ing 4.0 cm × 4.0 cm was excised from the inferior border of

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the mandible (Figs. 7 and 8) and sent for histopathological examination, which confi rmed the diagnosis of peripheral osteoma.

Discussion

An osteoma is a benign osteogenic tumor arising from the proliferation of cancellous or compact bone. Osteomas can be central, peripheral, or extraskeletal. A central osteoma arises from the endosteum and a peripheral osteoma from the periosteum, and an extraskeletal soft-tissue osteoma usually develops within muscle.2 The cause of slow-growing osteomas is obscure, but the tumor may arise from cartilage or bony periosteum. Whether osteomas are benign neo-plasms or hamartomas is not known.3 Although the exact etiology and pathogenesis of peripheral osteomas are still unclear, traumatic, congenital, infl ammatory, and endocrine causes have been considered possible etiologic factors.2 Structurally, osteomas can be divided into three types: those composed of compact bone (ivory) or cancellous bone, or a combination of both types of bone.3

Osteomas can occur at any age, but are found most fre-quently in individuals older than 40 years.3 Peripheral oste-omas occur most frequently in the frontal, ethmoid, and maxillary sinuses, and are uncommon in the jawbones.4 Of the jawbones, the mandible is more commonly involved than the maxilla. Osteomas are found most frequently on the posterior aspect of the mandible, commonly on the

lingual border of the ramus or inferior mandibular border. Our case involved the inferior border of the body of the mandible. The mandibular lesion may be exophytic, extend-ing outward into the adjacent soft tissues as in our patient.3 The osteoma may be attached to the cortex of the jaw by a pedicle or along a wide base,3 as seen in our patient.

Most peripheral osteomas grow very slowly and do not produce major symptoms. In many cases, the discovery of a peripheral osteoma is an incidental fi nding. Sometimes, depending on location, the size of the tumor may cause facial deformity, deviation of the mandible on opening, headache, or exophthalmos.2 The swelling is usually pain-less until its size or position interferes with function.3 In our patient, it was a large painless swelling causing facial asym-metry only.

Imaging of peripheral osteomas can involve traditional radiography (e.g., panoramic radiographs, Waters’ view) or CT. The use of CT with 3-D reconstruction results in better resolution and more precise localization.5

On radiological imaging, osteomas are well-defi ned radi-opaque masses with distinct borders. Osteomas composed solely of compact bone are uniformly opaque, while those containing cancellous bone show evidence of an internal trabecular structure. In our case, the osteoma consisted of dense compact bone and was uniformly opaque.3,5 Large lesions can displace adjacent soft tissues, such as muscles, as was seen in our patient.3

The removal of peripheral osteomas is not generally nec-essary. Surgery is indicated when the lesion is symptomatic or growing actively. The surgical approach should be case-specifi c. For the mandible, intraoral and extraoral approaches are possible.4 In this patient, the mass was excised using an extraoral approach.

References

1. Ertas U, Tozoqlu S. Uncommon peripheral osteoma of the mandi-ble: report of two cases. J Contemp Dent Pract 2003;4(3):98–104.

2. Woldenberg Y, Nash M, Bodner L. Peripheral osteoma of the max-illofacial region. Diagnosis and management: a study of 14 cases. Med Oral Patol Oral Cir Bucal 2005;10:139–42.

3. White S, Pharoah MJ. Benign tumor of jaw. In: White S, Pharoah MJ, editors. Oral radiology. Principles and interpretation, 5th edn. St. Louis: Mosby; 2004. p. 410–58.

4. Kaplan I, Calderon S, Bucher A. Peripheral osteoma of the mandi-ble: a study of 10 new cases and analysis of the literature. J Oral Maxillofac Surg 1994;52:467–70.

5. Bodner L, Bar-Ziv J, Kaffe I. CT of cystic jaw lesions. J Comp Assist Tomogr 1994;18:22–6.

Fig. 7. Intraoperative photograph showing excision of the mass

Fig. 8. Excised lobulated bony mass