Fig. 2

High-grade sarcoma with numerous non neoplastic osteoclast-type multinucleated giant cells (A: HE, 10x). It shows brisk mitotic activity (B: HE, 100x) and frequent atypical mitoses (C: HE, 400x). The whole tumor was submitted for histological analysis and few areas of equivocal osteoid matrix production were observed (C: 400x, HE stain). Atypical mononuclear cells show diffuse nuclear staining for SATB2 (E: 100x and F:400x) while only osteoclast-type multinucleated giant cells stained for marker of histiocytic differentiation, CD68 (G: 400x)