Fig. 3.

Micrograph of the resected lesion showing an area of the tumor featuring spindle cells within loose stroma with associated nuclear atypia and scattered mitotic figures (panel A; H&E stain. ×200). The microscopic field in panel B shows the presence of bony trabeculae surrounded by large malignant hyperchromatic, multinucleated bizarre cells (H&E stain ×200). Panel C shows the tumor acquiring a pleomorphic undifferentiated (malignant fibrous histiocytoma-like) pattern (H&E stain ×200). Panel D shows an area with chondrosarcomatous differentiation (H&E stain ×200).