Hypertrophic Mental Tubercles of the Mandible.

PURPOSE: Enlarged mental tubercles are rare benign exostoses that occur in children. The purpose of this study was to report a case series of patients with hypertrophic mental tubercles and propose a theory for their etiopathogenesis. PATIENTS AND METHODS: In this retrospective case series of patients with hypertrophic mental tubercles, we reviewed patients' medical records for age, gender, clinical presentation, findings on physical examination and radiographic images, and management details. Descriptive data were summarized. RESULTS: The sample included 14 patients (71% of whom were male patients) who presented at a mean age of 12.9 +/- 4.8 years (range, 6 to 21 years). Most patients had bilaterally enlarged mental tubercles (n = 8); unilateral cases were primarily on the left side (5 of 6 patients). On clinical examination, a bony prominence in the parasymphyseal region was noted on palpation and occasionally by visual inspection. No tenderness to palpation or overlying skin changes were noted. Typical radiographic features included asymmetry along the inferior border of the mandible in the parasymphyseal region on panoramic radiographs and prominence and/or enlargement of the mental tubercles on computed tomography scans. No evidence of cortical expansion, perforation, or periosteal reaction was found. Three patients requested contouring of the hypertrophied tubercles. CONCLUSIONS: Hypertrophic mental tubercles are rare bony exostoses that occur in children in a region where a confluence of facial muscles attach to the mandible. The etiology likely involves bone deposition occurring in an area of muscle pull.