case_images: PMC10778149_01
case_images: Histological findings and the results of special staining and immunostaining in case 3 are as follows: The tumor cells exhibit an organoid pattern (A) or a nest-like arrangement (B), with delicate fibrovascular septa separating them. PAS staining reveals the presence of purplish-red crystals in the cytoplasm (indicated by the yellow arrow) (C). Immunostaining shows diffuse positivity for TFE3 (D), while HMB-45 (E) and Melan-A (F) are negative. The original magnification for all images is 200x.
case_images: IJWH-16-17-g0002.jpg
case_images: PMC10778149_01_IJWH-16-17-g0002.jpg
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case_images: Pathological evaluation revealed large, round, or polygonal tumor cells growing in an organoid pattern (Figure 2A) or a nest-like arrangement (Figure 2B), separated by delicate fibrovascular septa. Periodic acid-Schiff-positive purplish-red crystals were observed in the cytoplasm (Figure 2C). Immunohistochemical staining was positive for TFE3 (Figure 2D) and CD56, but negative for HMB45 (Figure 2E), Melan-A (Figure 2F), Desmin, S-100, Syn, CgA, CD10, and Pax-8.
case_images: Fluorescence in situ hybridization demonstrates a break-apart signal indicating TFE3 rearrangement in case 3.
case_images: IJWH-16-17-g0003.jpg
case_images: PMC10778149_01_IJWH-16-17-g0003.jpg
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case_images: Fluorescence in situ hybridization showed break-apart signals for the TFE3 gene (Figure 3).
case_images: A diagrammatic representation is provided to illustrate the two variant gene fusions identified through targeted RNA sequencing analysis. The PRCC-TFE3 transcript consists of PRCC exon 7 fused to exons 2 of TFE3 in case 3.
case_images: IJWH-16-17-g0004.jpg
case_images: PMC10778149_01_IJWH-16-17-g0004.jpg
case_images: f0004
case_images: Whole exon sequencing identified a novel gene fusion between PRCC (NM_005973.4) exon 7 and TFE3 (NM_006521.4) exon 2 (Figure 4).