case_images: PMC5556985_01
case_images: CT imaging shows a heterogeneous partially calcified enhancing solid mass of the right kidney and gross findings show a necrotic and friable soft tissue mass involving the distal ureteric margin and the renal vein.
case_images: CRIU2017-1750694.001.jpg
case_images: PMC5556985_01_CRIU2017-1750694.001.jpg
case_images: fig1
case_images: Lesion is noted adjacent to and compressing the right renal artery with anteromedial displacement (Figure 1). Upon further dissection, the tumor was seen abutting the pelvis rather than invading it, although it did appear to obliterate the renal sinus (Figure 1).
case_images: Diffusely infiltrative small blue cell tumor, magnification (100x); round cells with scant cytoplasm and moderate degree of nuclear atypia, magnification (200x).
case_images: CRIU2017-1750694.002.jpg
case_images: PMC5556985_01_CRIU2017-1750694.002.jpg
case_images: fig2
case_images: Nephroblastoma, lymphoma, sarcomatoid renal cell carcinoma, and rhabdomyosarcoma were brought into the differential diagnostic considerations and were ruled out, and a diagnosis of renal PNET was offered (Figure 2).
case_images: Diffuse and strong membranous positivity for CD99, magnification (200x); diffuse and moderate nuclear positivity for FLI-1, magnification (200x).
case_images: CRIU2017-1750694.003.jpg
case_images: PMC5556985_01_CRIU2017-1750694.003.jpg
case_images: fig3
case_images: The histopathologic diagnosis was confirmed by immunohistochemistry with characteristic positivity for CD99 and FLI1 (Figure 3), as well as FISH studies documenting EWS gene rearrangement (Figure 4).
case_images: FISH studies: EWS gene rearrangement.
case_images: CRIU2017-1750694.004.jpg
case_images: PMC5556985_01_CRIU2017-1750694.004.jpg
case_images: fig4
case_images: The histopathologic diagnosis was confirmed by immunohistochemistry with characteristic positivity for CD99 and FLI1 (Figure 3), as well as FISH studies documenting EWS gene rearrangement (Figure 4).