case_images: PMC10824949_01
case_images: Representative clinical images for the tumor tissue in the right vulvar. (A) Computed tomography (CT) scans showed the patient's tumor mass (arrows). (B,C) HE staining (100x and 200x) of the tumor tissue showed bland spindle cells in a variably fibrous to myxoid stroma. In the fibrous area, the tumor cells showed a swirling growth or short bundle pattern that mixed with collagen fibers, whereas myxoid foci contained arched-shaped capillaries. (D,E) IHC examinations (100x and 200x) of the tumor tissue were positive for MUC4.
case_images: fmed-10-1343407-g001.jpg
case_images: PMC10824949_01_fmed-10-1343407-g001.jpg
case_images: fig1
case_images: In July 2022, a computed tomography (CT) revealed that the tumor recurred and had significantly increased to 10 x 3 x 3 cm (Figure 1A). There was no necrosis present and no areas characteristic of sclerosing epithelioid fibrosarcoma (SEF) (Figures 1B,C). Immunohistochemistry (IHC) analysis showed positive staining for high-mobility group AT-hook 2 (HMGA2), signal transducer and activator of transcription 6 (STAT6), Rb, and beta-catenin and negative staining for ER, smooth muscle myosin heavy chain (SMMHC), ALK, phosphorylated histone H3 (PHH3), CD34, PR, S-100, SOX10, caldesmon, and SMA (Supplementary Figure S1). The Ki67 index was 2% (Supplementary Figure S1). Additionally, the IHC of MUC4 was done, and its positivity supported the diagnosis of an LGFMS (Figures 1D,E).
case_images: Molecular genetic studies by next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH). (A) NGS sequencing reads indicating a fusion gene between FUS exon 6 and CREB3L2 exon 5 were demonstrated by Integrative Genomics Viewer (IGV) software. FISH analyses demonstrated positive for rearrangements of both the (B)
  FUS and (C)
  CREB3L2 loci, using the break-apart probe sets.
case_images: fmed-10-1343407-g002.jpg
case_images: PMC10824949_01_fmed-10-1343407-g002.jpg
case_images: fig2
case_images: FUS exon 6 and CREB3L2 exon 5 with a variant allele frequency (VAF) of 43.31% (Figure 2A). In addition, all the somatic mutations are presented in Supplementary Table S1. FISH analyses using the break-apart probe sets demonstrated positive rearrangements of both the FUS and CREB3L2 loci, thus confirming the NGS results (Figures 2B,C).