Abstract：
Extraskeletal myxoid chondrosarcoma (EMCS) is an undifferentiated mesenchymal malignancy; however, its immune microenvironment remains to be elucidated. The case of a 34-year-old woman who developed EMCS metastasizing to the pleura is presented here. The pleural EMCS showed hypervascularity, absent PD-L1 expression, and a lack of tumor mutational burden and pathogenic variants. Immunohistological examination of the pleural lesions showed predominant M2 macrophages and sparse CD8+ T cells. EMCS and the tumor stroma were positive for transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF). In contrast, a small number of the stromal vessels were positive for hypoxia inducible factor-1α (HIF-1α). TGF-β1 and VEGF in the tumor stroma and low antigenicity of the tumor cells may help explain how EMCS induced the immunosuppressive microenvironment. These findings may encourage investigators to explore novel combined immunotherapy for EMCS, such as TGF-β1 and VEGF inhibitors, and specific therapy for enhancing tumor antigens.
摘要：
骨外粘液样软骨肉瘤（EMCS）是一种未分化的间充质恶性肿瘤；然而，其免疫微环境仍有待阐明。这里介绍了一名34岁的妇女发生EMCS转移到胸膜的情况。胸膜EMCS显示血管过多，PD-L1表达缺失，缺乏肿瘤突变负担和致病变异。胸膜病变的免疫组织学检查显示主要的M2巨噬细胞和稀疏的CD8T细胞。EMCS和肿瘤间质的转化生长因子-β1（TGF-β1）和血管内皮生长因子（VEGF）阳性。相比之下,少量基质血管缺氧诱导因子-1α（HIF-1α）阳性。肿瘤基质中的TGF-β1和VEGF以及肿瘤细胞的低抗原性可能有助于解释EMCS如何诱导免疫抑制微环境。这些发现可能会鼓励研究人员探索针对EMCS的新型联合免疫疗法。如TGF-β1和VEGF抑制剂，和增强肿瘤抗原的特异性疗法。
