Abstract
A 24-year-old woman presented with a 7-week history of headache and left frontal scalp swelling. A plain radiograph and CT demonstrated a 2-cm lytic lesion in the frontal bone which was excised via craniotomy. Histology showed this to be an osteoma. Osteomas very rarely, if ever, appear as lytic lesions. The differential and radiological diagnoses are discussed.