PMC3270556_01
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 x20). (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 x100, 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).
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In addition, the kidney showed an 8.3 cm encapsulated tumor located at the pelvic adipose tissue within the renal capsule (Figure 1(a)). At places rosettes were identified (Figure 1(b)). Mitotic activity was present (Figure 1(c)). Table 1. The tumor cells were strong positive for neuron-specific enolase (Figure 1(d)), CD56 (Figure 1(e)), Cytokeratin AE1/3, and Cam 5.2. Ki 67 showed a high proliferation rate index of 30% (Figure 1(f)).
PMC3270556_02
Twenty-one-year-old female. (a) Bivalved right kidney: gross photography showing islands of tan tissue with hemorrhage and necrotic yellow friable areas (center). (b) Microphotography of the right atrial mass removed from the patient showing islands of small blue cells intermixed with necrotic material and blood. (c) The tumor cells showed positive membranous satins for CD99 (DAB X40). (d) Viable tumor cells positive for CD56, note that the necrotic cells are negative (DAB X40). (e) Synapthophysin was positive in the viable neoplastic cells in a cytoplasm dot-like pattern (DAB X40). (f) Fluorescent microphotography: normal cell lacking t(22; q12), a 2-fusion signal pattern is expected to be seen, reflecting the 2 intact copies of EWSR1. In abnormal cell (circle) with t(22; q12), a 1-fusion, 1 green, 1 orange signal pattern will be expected to occur. This confirmed the EWSR1 fusion transcripts in this peripheral primitive neuroectodermal tumor of the kidney.
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The histological examination of the right atrial, pulmonary artery, and caval vein thrombus revealed islands of uniform small round blue cells with scant cytoplasm, uniform nuclei, and stippled chromatin intermixed with necrosis and blood clot (Figure 2(b)). The viable tumor cells showed a strong membranous stains for CD99 (Figure 2(c)), focal membranous and cytoplasm stain for CD56 (Figure 2(d)), a cytoplasm dot pattern for synapthophysin (Figure 2(e)), and focal cytoplasm and membranous stain for PGP9.5, BCL2, and vimentin. Grossly, the right kidney revealed multifocal tan-brown to yellow masses in the upper and lower poles ranging from 0.4 x 0.4 cm to 4.3 x 2.8 cm (Figure 2(a)). Fluorescent in situ hybridization analysis using the 22q12 LSI, EWSR1, Dual-Color Break-Apart Probe was performed on fresh tissue and showed 57 (95.0%) of the cells with the translocation pattern 22q12 for the EWSR1 gene (Figure 2(f)).