Figure 2 Solitary fibrous tumor, microscopy. Microscopy
revealed a storiform pattern arranged in hypocellular and hypercellular
areas, necrosis of 20% of the tumor, and 6 mitoses in 10 high-power
fields. With the immunohistochemical markers it was possible to observe
positivity for CD99, CD34, Bcl-2, with actin and S100 being negative.
With these findings, the final diagnosis was a malignant solitary
fibrous tumor. (a) Storiform spindle cell proliferation,(b) CD99 positive, (c) CD34 positive, (d)Bcl-2 positive (all in 100x).