炎性肌纤维母细胞瘤的临床病理特征与鉴别诊断

Clinicopathological characteristics and differential diagnosis of inflammatory myofibroblastic tumor

目的 探讨炎性肌纤维母细胞瘤(IMT)的病理组织学特征、诊断要点与鉴别诊断。方法 对杨凌示范区医院和西安交通大学第一附属医院病理科2013年2月至2018年2月确诊的15例IMT的临床资料、病理特点进行回顾性分析,行免疫组化染色,采用荧光原位杂交技术(FISH)检测间变性淋巴瘤激酶(ALK)基因易位,并复习相关文献。结果 15例IMT中,女性8例,男性7例。发病年龄16~72岁,平均年龄(42.20±18.19)岁。发生于肺8例,大网膜及肠系膜5例,腹膜后1例,后纵隔1例。5例胸痛,其中1例伴呼吸困难;7例可触及包块伴随腹痛、消化不良;3例实验室检查出现贫血、血沉加快;2例无任何临床症状。镜检为肿瘤由增生的胖梭形纤维母/肌纤维母细胞组成,呈束状或漩涡状排列,间质内伴有大量炎细胞浸润,部分间质呈黏液水肿样或不同程度的胶原化。免疫组化肿瘤细胞表达ALK(15例中8例表达)、平滑肌肌动蛋白(SMA)、vimentin,部分表达广谱角蛋白(CK)、desmin,而CD117、S-100均阴性,1例腹部IMT表达P53,Ki-67阳性细胞指数均<10%。8例检测出ALK基因易位,7例未检测出ALK基因易位。结论 IMT是一种少见的低度恶性软组织肿瘤,因其形态温和、大量炎细胞浸润而易被误诊,诊断需结合病理组织学特征及免疫组化标记,必要时进行基因检测,且要与其他肿瘤性及炎性病变相鉴别。

Objective To investigate the histopathological features,diagnostic points and differential diagnosis of inflammatory myofibroblastic tumor(IMT).Methods The clinical data and pathological characteristics of 15 cases of IMT diagnosed in the pathology department of Yangling Demonstration Zone Hospital and the First Affiliated Hospital of Xi'an Jiaotong University from February 2013 to February 2018 were retrospectively analyzed.The immunohistochemical staining was taken,anaplastic lymphoma kinase(ALK)gene translocation was detected by fluorescence in situ hybridization(FISH),and the related literatures were reviewed.Results Among the 15 cases of IMT,there were 8 females and 7 males.The age of onset was 16-72 years old,the average age was(42.20±18.19)years old.There were 8 cases in the lung,5 cases in the greater omentum and mesentery,1 case in the retroperitoneum and 1 case in the posterior mediastinum.There were 5 cases of chest pain,including 1 case of dyspnea;7 cases of palpable mass with abdominal pain and dyspepsia;3 cases of laboratory tests showed anemia and accelerated erythrocyte sedimentation rate;2 cases without any clinical symptoms.Microscopic examination showed that the tumor was composed of proliferating fat spindle-shaped fibroblasts/myofibroblasts,arranged in bundles or whirlpools,with a large number of inflammatory cell infiltration in the stroma,and some stroma showed myxedema-like or varying degrees of collagenization.Immunohistochemically,the tumor cells expressed ALK(8 out of 15 cases),smooth muscle actin(SMA)and vimentin,and partially expressed pan-cytokeratin(CK)and desmin,while CD117 and S-100 were negative,one case of abdominal IMT expressed P53,and the Ki-67 positive cell index<10%.ALK gene translocation was detected in 8 cases and undetected in 7 cases.Conclusion IMT is a rare low-grade malignant soft tissue tumor.It is easily misdiagnosed because of its mild shape and a large number of inflammatory cell infiltration.The diagnosis should be combined with histopathological features and immunohistochemical markers.If necessary,genetic testing should be performed,and it should be distinguished from other neoplastic and inflammatory lesions.