Fig. 5

Photomicrographs of specimens collected during the first surgery. a Resection specimen shows a tumour comprising haphazardly proliferating high-grade spindle cells and an extracellular eosinophilic osteoid-like matrix. b Resection specimen shows a hypocellular area with brisk mitotic activity. Haematoxylin and eosin staining, original magnification ×400 (a–b). c Immunostaining of a resection specimen with primary antibodies to CD34 shows diffusely positive cells. Original magnification ×400