Button Osteoma: A Review of Ten Cases

BACKGROUND: Button osteoma presents as small circumscribed ivory-like lumps on the skull vault. Although not rare, its diagnosis can be challenging for dermatologists. OBJECTIVE: To clarify the clinical characteristics of button osteoma by reviewing 10 cases. METHODS: Ten patients diagnosed with button osteoma at the Department of Dermatology, Kyungpook National University Hospital, between January 2011 and August 2014 were enrolled. We retrospectively reviewed medical records and analyzed demographic and clinical characteristics including sex, age, sites, number of lesions, symptoms, duration, histopathological finding, radiological findings, and treatment. RESULTS: All patients presented with an asymptomatic small circumscribed hard lump fixed to a bony structure. There were 9 female and 1 male patient, and the mean age was 54 years (range, 28~61 years). The most common site was the forehead, and disease duration ranged from 2 weeks to more than 20 years. The differential diagnosis included cranial exostosis, ballooned osteoma, epidermal cyst, and lipoma. Simple radiography, ultrasonography, and computed tomography (CT) were used to make a confirmative diagnosis. Histopathological findings showed lamellated bony structures with poor vascularization. Ostectomy was performed for 5 patients, and no recurrence was detected within an average of 13.4 months after treatment. CONCLUSION: This review characterized button osteoma. Surgical excision is a useful therapeutic modality after CT-based diagnosis. Further studies with more patients are required to confirm the findings.