Exostoses are benign, exophytic bony outgrowths composed predominantly of cortical bone, the dense outer shell of the skeleton, though they sometimes contain cancellous bone, the spongy tissue found inside. They arise from the cortical surface of the jaws, are typically covered by normal-looking mucosa, and present as hard, painless masses on palpation. These lesions may be solitary or multiple, and their morphology can range from nodular to pedunculated, meaning attached by a stalk. Most commonly, they appear bilaterally on the buccal aspect of the maxillary alveolar ridge—the cheek side of the upper jaw’s tooth-bearing bone—while involvement of the mandible, the lower jaw, is comparatively rare. That rarity is precisely what made this young patient’s presentation noteworthy to the surgical team.

The precise cause of exostoses remains uncertain, but researchers have proposed several contributing factors. Genetic predisposition is thought to play a role, alongside environmental influences, masticatory hyperfunction—essentially, excessive chewing forces—and occlusal stress from the way the teeth meet. From a molecular perspective, bone remodeling–related genes such as RUNX2, a master regulator of osteoblastic differentiation and bone formation, have been suggested as potential contributors to abnormal bony growth patterns. Clinically, these lesions are often differentiated by location and morphology. Torus palatinus occurs along the midline of the hard palate, while torus mandibularis appears on the lingual, or tongue-facing, surface of the lower jaw, typically in the premolar to molar region. Histopathologically, however, exostoses and tori are indistinguishable: both consist of mature cortical and trabecular bone.

The epidemiology of these growths is striking. Studies report variable prevalence across populations, with torus palatinus occurring in up to 66 percent of individuals and torus mandibularis in up to 63.4 percent, while buccal exostoses have a lower prevalence of approximately 26.9 percent. Exostoses are usually asymptomatic and are most often discovered incidentally during routine dental examinations. They tend to occur more frequently in older individuals, particularly males, which makes an 18-year-old female with a solitary anterior mandibular lesion an atypical demographic on two counts. Recent studies indicate that buccal exostoses are less frequently reported than tori and predominantly occur in the posterior regions of the jaws. Anterior mandibular involvement is rare and mainly documented as isolated case reports, and the true incidence may be underestimated due to underreporting and population variability.

In this case, the patient presented to a maxillofacial surgeon with a swelling in the anterior region of her mandible that had been present for several months and had become a cosmetic concern, although it had not grown recently. Intraoral examination revealed a solitary, round, bony-hard prominence in the anterior buccal region. The overlying mucosa appeared normal, and the lesion was non-tender and immobile. There were no signs of facial asymmetry or functional impairment in speaking, chewing, or biting. The adjacent teeth were vital, with no mobility or sensitivity, and the patient had no history of parafunctional habits, trauma, or temporomandibular joint disorders. Her medical history was unremarkable, and notably, she reported no family history of exostoses—neither parent presented with similar bony protuberances—suggesting the absence of a hereditary predisposition in this instance.

Imaging played the decisive diagnostic role. The team performed a CBCT scan using a NewTom Giano HR device with a voxel size of 0.2 millimeters, a resolution fine enough to capture submillimeter anatomical detail. Multiplanar reconstructions in the axial and sagittal planes, along with three-dimensional renderings, demonstrated a well-defined, localized bony mass arising from the buccal cortex of the anterior mandible between the left central and lateral incisors. Critically, there was no evidence of invasion into adjacent structures, no root resorption, and no associated pathological changes. The differential diagnosis included buccal exostosis, osteoma, and peripheral ossifying fibroma. Correlating the imaging findings with the clinical presentation, the team established a provisional diagnosis of mandibular buccal exostosis and planned an excisional biopsy for definitive histopathological confirmation.

The choice of CBCT over conventional panoramic radiography was well justified by the physics of each modality. Panoramic radiography, the traditional first-line imaging tool for jaw lesions, is limited by magnification and distortion, with dimensional errors reported in the range of 15 to 25 percent for three-dimensional bony lesions. CBCT, by contrast, provides submillimeter accuracy of approximately 0.2 to 0.4 millimeters and eliminates the superimposition of overlapping structures, offering clearer visualization of cortical boundaries and adjacent anatomy. On CBCT, exostoses appear as well-defined cortical outgrowths with uniform density and direct continuity with the adjacent cortex, lacking internal heterogeneity, soft-tissue involvement, or expansile behavior. These quantitative advantages make CBCT considerably more reliable for assessing small anterior mandibular outgrowths that may be underestimated on panoramic images.

Distinguishing benign bone lesions from more aggressive pathologies is critical for appropriate management, and the imaging signatures differ in telling ways. Osteomas typically show higher radiodensity, a mixed cortical-cancellous pattern, and a more compact trabecular architecture; they are uncommon in the anterior mandible and occur more frequently in the paranasal sinuses. Peripheral ossifying fibroma, although primarily a soft-tissue lesion, may present with irregular internal calcifications and heterogeneous radiopacity—features absent in exostoses. Malignant tumors such as osteosarcoma and chondrosarcoma, meanwhile, often exhibit rapid growth, cortical destruction, and ill-defined margins. In this case, the lesion’s homogeneous cortical density, smooth margins, and direct cortical continuity were consistent with exostosis rather than osteoma or peripheral ossifying fibroma, guiding the team toward conservative surgical excision.

The surgery itself was performed under local anesthesia. The team raised a full-thickness triangular mucoperiosteal flap to expose the lesion, then excised the bony mass using a fissure bur and an osteotome. The surgical site was smoothed and contoured with a round carbide bur to restore continuity with the surrounding cortical bone. The excised specimen was submitted for anatomopathological examination, which confirmed the diagnosis of a benign exostosis composed of mature cortical and trabecular bone. Postoperative care included analgesics, antibiotics, and chlorhexidine mouthwash. Healing was uneventful, and follow-up visits at two weeks, three months, six months, and one year demonstrated satisfactory soft-tissue healing, preservation of the normal buccal contour, and no palpable bony irregularity at the surgical site.

The outcome carried meaningful psychological weight for the patient. Her chief concern had been cosmetic, and she reported significant improvement in self-confidence related to her facial appearance and speech after removal of the lesion. At the one-year follow-up, she reported no pain, discomfort, sensory disturbance, or functional limitation during speech, mastication, or oral hygiene procedures. The esthetic result was satisfactory, and no clinical evidence of recurrence was observed throughout the follow-up period. Because no signs or symptoms suggested complications or regrowth, the authors did not consider additional radiographic follow-up clinically necessary. The case aligns with standard management principles: exostoses are typically managed conservatively, with surgery indicated only when a lesion interferes with prosthodontic appliance placement, causes chronic mucosal ulceration, or produces esthetic or psychological concerns.

Comparisons with previously reported cases underscore just how unusual this presentation was. One earlier report documented a solitary exostosis in the right mandibular canine region that caused gingival recession around a single tooth—a contrast with the present case, where the adjacent teeth were entirely unaffected. Another described a young female with bilateral localized exostoses of the maxilla, differing in both anatomical location and lesion distribution. A third reported multiple exostoses in the anterior mandible of a 38-year-old woman, spanning the canine-to-canine region; although the anatomical site was similar, the multiplicity of lesions distinguished that case from this solitary example. In all reported cases, surgical excision was undertaken, and histopathological evaluation proved essential to confirm the benign nature of the lesions and rule out other pathologies.

The authors are candid about the limitations of their report, noting its single-center nature and inherently small sample size. The findings are descriptive and should not be interpreted as generalizable evidence; rather, the clinical observations are intended to contribute to the existing literature on rare mandibular buccal exostosis cases. Even so, the report delivers a clear message for clinicians and curious readers alike: unusual maxillofacial bone lesions demand a combination of thorough clinical assessment and appropriate imaging tools. CBCT, while not the primary diagnostic modality for such lesions, provided valuable complementary imaging that aided surgical planning and helped confirm the benign nature of the mass. For an 18-year-old worried about a lump on her jawline, that combination of careful diagnosis and precise surgery restored both her bone contour and her confidence—with no sign of the growth returning a year later.

Subject of Research: Diagnosis and surgical management of a rare anterior mandibular exostosis using cone-beam computed tomography

Article Title: Management of Anterior Mandibular Exostosis With Cone‐Beam Computed Tomography: A Rare Case Report

Article References: Abbasi, S., & Mohebiniya, M. (2026). Management of Anterior Mandibular Exostosis With Cone‐Beam Computed Tomography: A Rare Case Report. Clinical Case Reports, 14(10), Article e73565. https://doi.org/10.1002/ccr3.73565

Image Credits: AI Generated

DOI: 10.1002/ccr3.73565

Keywords: exostosis, mandible, cone-beam computed tomography, oral surgery, benign bone lesion, torus, osteoma, differential diagnosis, maxillofacial surgery, case report, dental imaging, bone remodeling