Fig. 5.

Secondary malignant giant cell tumor of Bone. (Fig. 5-A) and (Fig. 5-B) came from one case. (Fig. 5-C) and (Fig. 5-D) came from another case. (Fig. 5-A) and (Fig. 5-C) showed the classical giant call tumor from the initial lesion respectively. (Fig. 5-B) Illustrated the osteosarcoma in the recurrence lesion. (Fig. 5-D) Demonstrated the high-grade undifferentiated pleomorphic sarcoma in the recurrence lesion (H&E × 200).