EWSR1-SMAD3重排纤维母细胞性肿瘤1例并文献复习

EWSR1-SMAD3-rearranged fibroblastic tumor: a case report and review of literature

目的探讨EWSR1-SMAD3重排纤维母细胞性肿瘤(EWSR1-SMAD3-rearranged fibroblastic tumor,ESFT)的临床病理学特征、诊断及鉴别诊断。方法回顾性分析1例ESFT的临床病理学、免疫表型及影像学特点;采用FISH技术检测EWSR1基因易位,并复习相关文献。结果患者女性,25岁,临床表现为左手小指近端指骨尺侧皮下结节10余年。X线示皮下界限欠清的软组织结节。肿瘤大体呈结节状,无包膜,切面灰白色,实性、质韧。镜下肿瘤由纤维母细胞样梭形细胞组成,呈特征性的外周富于梭形细胞束而中央细胞稀少伴玻璃样变性的分带状结构,瘤细胞形态一致,无异型性,核仁不明显,核分裂象罕见。免疫表型:瘤细胞vimentin和ERG弥漫强阳性。ALK、BCL-2、CK(AE1/AE3)、MDM2、CDK4、CD99、CD34、CD31、Calretinin、h-Caldesmon、β-catenin、desmin、EMA、α-SMA、S-100、SOX10、STAT6、NTRK1和H3K27me3均阴性。Ki-67增殖指数<2%。FISH检测显示肿瘤具有EWSR1基因易位。结论ESFT是一种好发于肢端的罕见、具有局部侵袭性的良性纤维母细胞性肿瘤。典型形态结合免疫表型和EWSR1基因易位检测有助于诊断及鉴别诊断。

Purpose To investigate the clinicopathological features of EWSR1-SMAD3-rearranged fibroblastic tumor(ESTF)and its differential diagnoses.Methods Combined with the clinical and imaging data,a case of ESTF was studied with histopathological observation and immunohistochemical staining.The fluorescence in situ hybridization(FISH)was performed in the paraffin-embedded tissue of ESFT,using the EWSR1 dual color break-apart probe.The related literatures were reviewed.Results The patient was a 25-year-old female,and the clinical manifestation was a subcutaneous nodule on the ulnar side of the proximal phalanx of the left little finger for more than ten years.Radiographically,the lesion was a subcutaneous soft tissue nodule with unclear boundary.Grossly,the tumor was a nodule without capsule,and the section was gray white,solid and tough.Histologically,the tumor was composed of uniform fibroblastic spindle cells which lack nuclear atypia,pleomorphism,prominent nucleoli,and mitotic activity.A distinctive zonal pattern with acellular central hyalinization and peripheral area of cellular spindle cell fascicles was present in the case.Immunohistochemically,the tumor showed diffusely strong nuclear staining for ERG and vimentin.While ALK,BCL-2,CK(AE1/AE3),MDM2,CDK4,CD99,CD34,CD31,Calretinin,h-Caldesmon,β-catenin,desmin,EMA,α-SMA,S-100,SOX10,STAT6,NTRK1 and H3K27me3 were all negative.The Ki-67 labeled proliferative index was<2%.The tumor was shown to harbor EWSR1 gene rearrangement by FISH.Conclusion ESFT is a rare,benign but locally aggressive fibroblastic tumor.The typical pathological morphology combined with immunophenotyping and EWSR1 gene detection is helpful for the diagnosis and differential diagnoses.