Fascicles of polygonal-spindle cells
Pale eosinophilic cytoplasm
Round-ovoid nuclei with pleomorphism; inconspicuous mitotic activity
Foci of osteoid deposition
Sheets and fascicles of polygonal-spindle cells
Pale amphophilic cytoplasm
Round-ovoid nuclei with macronucleoli, and marked pleomorphism; conspicuous mitotic activity
Foci of osteoid and chondroid deposition
Haemorrhagic cyst-like spaces with multinucleated giant cells
Sheets of polygonal-spindle cells
Pale amphophilic cytoplasm
Round-ovoid nuclei with hyperchromasia and marked pleomorphism; conspicuous mitotic activity
So-called "malignant" osteoid