子宫腔EWSR1-POU5F1融合小圆细胞未分化肉瘤临床病理观察

Small round cell undifferentiated sarcoma with EWSR1-POU5F1 fusion in uterine cavity:clinicopathological analyses

目的探讨子宫腔EWSR1-POU5F1融合小圆细胞未分化肉瘤的临床病理特征、诊断及鉴别诊断。方法对1例子宫腔EWSR1-POU5F1融合小圆细胞未分化肉瘤进行组织学观察、免疫组化染色、NGS、FISH、qRT-PCR及Sanger测序,并结合相关文献讨论其临床病理特征。结果患者32岁,经量增多伴经期延长3个月余。肿瘤发生于子宫腔,呈弥漫菜花状,大小约10 cm×7 cm×3 cm。肿瘤细胞呈分叶状或巢状排列,伴丰富的血管纤维结缔组织。细胞呈小圆形或短梭形,细胞质较少,部分透亮,细胞核呈圆形或卵圆形,核型欠规则,核分裂象多见。肿瘤细胞Vimentin(弱+)、CD99(弱+)、Syn(+)、CD56(+)、S-100(-),上皮及平滑肌源性标记均阴性。NGS、qRT-PCR和Sanger测序均检测到EWSR1-POU5F1融合性基因,FISH检测示EWSR1分离阳性。结论EWSR1-POU5F1融合小圆细胞未分化肉瘤是一种较为罕见EWSR1-nonETS重排肉瘤,恶性程度较高,诊断及鉴别诊断需要结合临床、病理形态学及分子检测结果。

Objective To investigate the clinicopathological features,diagnosis and differential diagnosis of EWSR1-POU5F1 fusion small round cell undifferentiated sarcoma in uterine cavity.Methods Histological observation,immunohistochemical staining,NGS,FISH,qRT-PCR and Sanger sequencing were performed in one case of uterine EWSR1-POU5F1 fusion small round cell undifferentiated sarcoma,and the clinicopathological features were discussed in combination with relevant literature.Results The patient was 32 years old with increased menstrual volume and prolonged menstrual period for more than 3 months.The tumor occurred in the uterine cavity in diffuse cauliflower shape,with a size of about 10 cm×7 cm×3 cm.The tumor cells were lobed or nestlike,with abundant vascular fibrous connective tissue.The cells were small round or spindle,the cytoplasm was less,part of the bright,the nucleus was round or spindle,the karyotype was not regular,the mitotic figure was commonly noted.The tumor cells were positive for vimentin(weak),CD99,Syn and CD56,but negative for S-100 and epithelial and smooth muscle markers.EWSR1-POU5F1 fusion gene was detected by NGS,qRT-PCR and Sanger sequencing,and separated signals of EWSR1 was detected by FISH.Conclusion Small round cell undifferentiated sarcoma with EWSR1-POU5F1 fusion is a rare EWSR1-nonETS rearranged sarcoma with a high degree of malignancy.Diagnosis and differential diagnosis should be combined with clinical,pathological and molecular findings.