Fig. 5.

Gross section of the kidney showing the tumor, which is ill-defined, grayish white and a homogenously firm appearance (arrows) (a). On medium power, the cellular part of the tumor showing the spindle cell proliferation with the chronic mononuclear inflammatory cell infiltrate (arrow) seen near the center (H&E) (b). On high power, the cellular part of the tumor shows bland plump spindle cells (circle) with proliferation, with keloid-like areas (arrow) and hyalinization in between the cells (H&E) (c). On medium power, areas of dystrophic calcification (arrowheads) can be seen within the tumor. (H&E) (d).