PMC2713886_01
A 43-year-old woman with subdural osteoma.. A. Radiograph of the left lateral skull depicts a radiopaque lesion (arrows) in the frontal area.. B. CT scan reveals the presence of a lentiform ossified lesion (arrows) in the left frontal area (window width: 90; window level: 25).. C. Bone window setting shows a lucent line (arrows) between the ossified lesion and the inner table of the skull (window width: 2000; window level: 200).. D. Intraoperative radiograph depicts an ossified lesion (arrows) under the craniectomy site.. E. Intraoperative photograph indicates that the lesion (arrows) is firmly attached to the reflected dura (arrowheads).. F. Microscopically, the tumor consists of a well-formed mature lamellar bone beneath the fibrous membrane (dura mater) (arrows) (H & E staining, x40).
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F1
Skull radiography, however, revealed the presence of an ovoid radiopaque lesion in the left frontal area (Fig. 1A), and computed tomography (CT) depicted a lentiform ossified lesion in the left frontal skull, obliterating the adjacent CSF space (Fig. 1B). At a bone window width/level setting of 2500/200, a curvilinear lucent line was noted between the inner table of the skull and the ossified mass (Fig. 1C). The surface of the dura mater at the craniotomy site was smoothly elevated, however, and intraoperative radiography showed that the cause of this was an ossified lesion (Fig. 1D). It was firmly attached to the inner surface of the dura (Fig. 1E), compressing the underlying brain, but not adhering to the arachnoid membrane. Histologically, the lesion consisted of mature lamella bone, made of Haver's system, and normal osteocytes between osteoid layers (Fig. 1F).