背景:骨外粘液样软骨肉瘤(EMCs)是具有遗传和生物学特征的实体瘤。只有少数研究讨论了KIT基因或CD117表达在EMC中的作用,通过免疫组织化学(IHC)染色鉴定。在这里,我们提出了一个新的细胞EMC表现出EWSR1-NR4A3融合,KIT外显子13突变和CD117强弥漫性表达。
方法:一名69岁男子左肩有一个拳头大小的肿瘤。CT显示左侧胸部和背侧肌肉间隙有肿瘤。肿瘤完全切除。组织学上,肿瘤细胞呈结节状结构,浸润周围脂肪和肌肉组织。肿瘤细胞大小均匀,细胞核呈圆形,明确的核仁和嗜酸性细胞的细胞质。免疫组织化学,肿瘤细胞CD117,波形蛋白,CD56和NSE和局灶性表达的结蛋白;细胞肌原蛋白阴性,S-100,SYN,INSM1,CD34,STAT6,INI-1,Brachyury,ERG,TLE1、AE1/AE3、WT-1、CD99和SMA。NGS显示EWSR1-NR4A3融合和KIT外显子13突变。病人手术后没有进一步治疗,随访10个月无复发或转移。
结论:分子检测是诊断细胞EMC必不可少的技术。本病例报告中提到的KIT突变可能为EMCs治疗选择提供新的见解。
BACKGROUND: Extraskeletal myxoid chondrosarcomas (EMCs) are solid tumors that have been genetically and biologically characterized. Only a few studies have discussed the role of the
KIT gene or CD117 expression in EMCs, identified by immunohistochemical (IHC) staining. Herein, we present a novel case of cellular EMC exhibiting an EWSR1-NR4A3 fusion,
KIT exon 13 mutations and strong diffuse expression of CD117.
METHODS: A 69-year-old man presented with a fist-sized tumor on his left shoulder. CT revealed a tumor in the left thoracic and dorsal muscle space. The tumor was completely resected. Histologically, the tumor cells had a nodular structure and infiltrated the peripheral fat and muscle tissues. The tumor cells were uniform in size with round nuclei, well-defined nucleoli and eosinophilic cytoplasm. Immunohistochemically, the tumor cells were positive for CD117, vimentin, CD56 and NSE and focally expressed desmin; the cells were negative for myogenin, S-100, SYN, INSM1, CD34, STAT6, INI-1, Brachyury, ERG, TLE1, AE1/AE3, WT-1, CD99 and SMA. NGS revealed an EWSR1-NR4A3 fusion and
KIT exon 13 mutations. The patient had no further treatment after surgery, and no recurrence or metastasis occurred during the ~ 10 month follow-up period.
CONCLUSIONS: Molecular detection is an indispensable technique for diagnosing cellular EMCs. The
KIT mutations noted in this case report may offer fresh insights into EMCs treatment options.