(a, b) X-ray showing a homogeneous sclerotic mass in the frontal bone of the skull. (c) MRI clearly shows a parosteal osteoma arising in the inner table of the skull projecting into the frontal lobe

(a, b) Anteroposterior and lateral x-ray of the skull. Note a surface radiodense mass. (c, d) Coronal and axial CT scan clearly defines the lesion as a parosteal osteoma arising in the outer table of the parietal bone. The lesion is attached to the cortical surface with a broad base. In large lesions the underlying cortex may show radiolucencies that correspond to blood vessels that feed the tumor. (e) Gross surgical specimen. (f) Cut surface of the lesion. Dense and compact (ivory-like) lesion with well-defined margins