378940.fig.004a
(a)
378940.fig.004b
(b)
Figure 4: (a) Low-powered view of the bony portion of the tumor demonstrates numerous irregularly shaped bony trabeculae. In most areas, the bony trabeculae are associated with a mildly cellular spindle cell proliferation and small capillaries (arrows). (b) High-powered view demonstrates bony trabeculae rimmed by osteoblasts (arrows). These are associated with a mildly cellular fibrovascular stroma with no significant nuclear pleomorphism or mitotic activity. These findings raise the possibility of osteoblastoma.