Objective:To discuss the clinicopathological features,immunophenotyping,diagnosis and differential diagnosis of the malignant solitary fibrous tumors (MSFT) for clarifying the diagnostic criteria.Methods:A retrospective analysis of the data of 7 cases MSFTs have been conducted from Dec 2011 to May 2014 by evaluating the follow-up results and related articles.Results:Among the 7 patients,3 were male,and 4 were female.The age were 33~72 years old,with the average age of 47.9 years old.The tumor sites reported here were kidney,prostate,retroperitoneum,tentorium cerebelli,scapular region,occiput and vola respectively,with the greatest diameter of those tumors varying from 2.8~11.2cm.Although some of these cases retained the special features of benign SFT,some malignant characteristics were present in all of those cases,including high cellularity,pleomorphism,more than 4 mitotic figures per 10HPFs,hemorrhage and necrosis.In addition,one special case showed epithelioid differentiation in focal areas with structures of small solid nests or pseudoglands arranged by oval or round tumor cells.Immunohistochemical studies revealed that tumor cells were strongly positive for vimentin,while the markers of CD34,CD99 and BCL-2 showed different expression,and the positive rate of STAT6 was 85.7%.Besides that,two cases focally expressed Keratin,one focally expressed EMA and another one focally expressed Calponin.Conclusion:The paper have made a comprehensive analysis of MSFTs in this article,and first reported the case containing the features of epithelioid differentiation in focal areas.Unlike benign SFT,most MSFTs did not co-express those three markers including CD34,CD99 and BCL-2.Having high rates of recurrence and metastasis,the prognosis of patients is not good.%目的:探讨恶性孤立性纤维性肿瘤的临床病理特点、免疫表型、诊断和鉴别诊断,以提高对其临床及病理改变的认识.方法:回顾性分析7例恶性孤立性纤维性肿瘤的临床特征、组织学形态及免疫组化结果,并复习相关文献结合随访结果进行讨论.结果:7例患者中,男性3例,女性4例,年龄33~72岁,平均47.9岁.发生部位:肾脏、前列腺、腹膜后、小脑幕、肩胛区、枕部和足底.肿瘤直径2.8~11.2cm.镜下:尽管部分病例中仍保留良性孤立性纤维性肿瘤的特殊形态学特征,但所有病例都具备一些恶性的指征,包括瘤细胞密度较高、异型性明显、核分裂象多见(>4个/10HPF)以及出血和坏死.除以上特点之外,本文病例中有一例局灶出现上皮样分化,即卵圆形或圆形肿瘤细胞呈巢片状或假腺样排列.免疫表型:vimentin呈弥漫强阳性表达,CD34、CD99和BCL-2表达情况各不相同,STAT6阳性率为85.7%.另外,2例病例局灶表达Keratin,1例局灶表达EMA,1例局灶表达Calponin.结论:本文综合分析了七例恶性孤立性纤维性肿瘤的临床病理特点,而且首次报道了1例"具有上皮样特征的"MSFTs.与经典型良性SFT不同,大部分MSFTs或多或少缺失三种标志物(CD34、CD99和BCL-2)的表达.MSFTs的预后不佳,易复发和转移.
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