Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Kidney: Two Unusual Presentations of a Rare Tumor
Figure 1
Thirty-two-year-old patient, right-sided laparoscopic radical nephrectomy. (a) Gross picture of the right kidney showing an 8.3 cm encapsulated tumor located at the pelvic adipose tissue within the renal capsule. (b) Microscopic photography of the tumor showing tumor cells arranged in solid sheets, tightly packed cords, and trabeculae with variable stroma. Tubular structures (arrow) can be identified in the periphery of the cell nests (HE ×20). (c) High power view of the tumor cells showing uniform small round blue cells with scant cytoplasm, uniform nuclei, and stippled chromatin. Mitotic activity (arrow) was present (HE ×100, oil). (d) The tumor cells were strongly positive for NSE in a cytoplasmic stain (DAB X50). (e) Strong membranous and cytoplasmic stain for CD56 (DAB X50). (f) Ki 67 shows a high proliferation rate index of 30% (DAB X50).
