Paraffin sections show fragments of an intensely vascular, moderately hypercellular tumor with a meningeal attachment. Vascular spaces vary from large caliber thin-walled sinuses down to capillaries. The latter enclose lobules of cells with features consistent with stromal cells. No mitotic figures or areas of necrosis are identified.
Immunohistochemistry shows negative staining for EMA, inhibin, CD34, GFAP, CAM5.2, S-100, tyrosinase and ALK-1.
This case exemplifies the difficulty in reconciling various factors (location, appearance, demographic) when appearances are unusual. It also highlights the fact that their pial origin makes a distinction between intra- vs extra-axial difficult.