Figure 7. Histopathological findings of the surgical specimen.

Microscopic examination (hematoxylin and eosin (H&E) staining; magnification, 200x ; scale bar, 50µm) showing a fibro-inflammatory tissue (red arrow) comprising a tumor proliferation made of nests and masses of medium- to large-sized cells with a few foci of keratinization and a few cell union bridges. A multitude of cytonuclear atypia with atypical mitoses (orange arrow). This tumor proliferation invades the bone tissue with lots of bony spaces surrounded by tumor masses.