Figure 2.

Images of histology and immunohistochemistry staining of tumour tissue. (A) Low power view revealing a partially circumscribed tumor with occasional irregular borders lying within the subcutaneous fat of the skin. Note the presence of blood vessels with staghorn appearance (indicated by arrow) and hemosiderin deposition. (H&E, magnification ×20). (B) Medium power view disclosing a proliferation of slender to plump spindle cells in fascicles with storiform arrangement (indicated by arrow) in some areas in association with osteoclast like multinucleated giant cells. (hematoxylin and eosin, original magnification ×100). (C) Decoration of spindle cells by antibody against CD163 on high power view. Note that the lack of pick up in the multinucleated giant cells (Ventana Optiview, original magnification ×600). (D) Factor XIIIa staining highlighting the multinucleated giant cells. (Ventana Optiview, original magnification ×400). Scale bars = 100 µm.