PMC3457717_01
MRI scan demonstrates the recurred tumor mostly involved right posterior fossa.
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fig1
CT (Figure 1) showed the recurrent tumor at original torcular site was increased in size. Craniotomy with total excision of the tumor was done. 
Histology and immunohistochemistry of meningeal hemangiopericytoma. (a) H&E 20x A hypercellular tumor with staghorn blood vessels. (b) Immunostaining of CD99 is diffuse and strong positive. (c) Immunostaining of CD 34 reveals variable positive.
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fig2
Staghorn or ectatic blood vessels are seen in some areas (Figure 2(a)). Immunohistochemically the neoplastic cells characteristically express diffusely CD99 (Figure 2(b)) and bcl2 and variable CD34 (Figure 2(c)), whereas no immunoreactivity was seen for EMA or progestogen receptor.