EWSR1-NFATC2 and FUS-NFATC2 Gene Fusion-Associated Mesenchymal Tumors: Clinicopathologic Correlation and Literature Review

Figure 3

CT imaging in a 60-year-old woman showed an isolated upper intraabdominal mass ((a) red asterisk). (b) Moderately cellular tumor with a prominent chondromyxoid matrix and trabecular growth pattern (H&E stain; original magnification 200x). (c) Rare mitoses are present (arrows) (H&E; 400x). (d) Heterogeneous proliferation index of up to 30% (MIB1 immunohistochemistry; 200x). (e) No rearrangement of the NR4A3 gene in FISH analysis, excluding extraskeletal myxoid chondrosarcoma (arrows: exclusively fused signals). (f) Break-apart FISH analysis of the EWSR1 gene demonstrated an unusual pattern of one to three fused signals (white arrows) and low-grade amplified red signals (red arrows) in tumor cell nuclei, suggesting rearrangement of the EWSR1 gene with additional chromosomal aberrations.