摘要目的:探讨膀胱炎性肌纤维母细胞肿瘤（IMT）临床病理学特点、免疫表型、分子遗传学改变、诊断与鉴别诊断。方法:收集宁波市临床病理诊断中心2011年9月至2020年12月诊断的3例和上海交通大学医学院附属瑞金医院2011年6月至2020年12月诊断的5例及2例会诊病例共10例IMT患者的临床和病理学资料，采用EnVision法进行免疫组织化学标记，应用荧光原位杂交（FISH）检测ALK基因的重排情况。结果:患者男性8例，女性2例。年龄范围16~62岁，中位年龄36岁。主要临床症状为血尿和尿路刺激症状，3例位于膀胱顶部，左侧壁4例，右侧壁3例。肿瘤最大径1.5~8.5 cm。8例病变主要位于黏膜下，部分区域累及肌层；2例病变主要位于肌层内，膨胀性浸润性生长，局灶侵及黏膜固有层及外膜。镜下特点，4例为结节性筋膜炎样型，3例为纤维组织细胞瘤样型，2例为混合型，1例呈平滑肌肉瘤样。免疫组织化学示10例病例平滑肌肌动蛋白（SMA）均阳性，9例Calponin阳性，6例结蛋白阳性，9例广谱细胞角蛋白（CKpan）阳性，9例间变性淋巴瘤激酶（ALK）阳性［其中7例ALK1胞质阳性，8例ALK（5A4）胞质阳性，7例ALK（D5F3）核质阳性］。8例行FISH检测，其中5例显示ALK基因重排阳性。随访8例，无复发及转移。结论:膀胱IMT是一种少见的中间型的具有恶性潜能的间叶性肿瘤，具有特殊的临床病理特征，较少发生复发。

abstracts0bjective To investigate the clinicopathological features,immunohistochemical phenotypes, molecular genetic alterations,diagnosis and differential diagnosis of inflammatory myofibroblastic tumor (IMT) of the urinary bladder. Methods:Ten cases of IMT of the urinary bladder (three cases at Ningbo Diagnostic Pathology Center from September 2011 to December 2020, five in-house diagnosed cases and two consultation cases at Shanghai Rui Jin Hospital from June 2011 to December 2020) were collected retrospectively. The clinicopathologic features and immunophenotypic profiles were studied by light microscopy and immunohistochemistry (EnVision method). The translocation of ALK gene was detected by fluorescence in situ hybridization (FISH).Results:Of the 10 patients, eight were male and two were female. The patients′ age range was 16 to 62 years (median 36 years).The main clinical presentation was hematuria and urinary irritation. Three cases were located at the dome of the urinary bladder, four cases were in the left lateral wall and the remaining three cases were in the right lateral wall. The tumor size ranged from 1.5 cm to 8.5 cm. In eight cases, the tumors were mainly submucosal, and in some cases extending to the muscular layer of the urinary bladder. In two cases, the tumors were mainly located in the muscular layer and focally extended to the submucosa and adventitia. Histologically, four cases had the nodular fasciitis-like pattern, three cases had fibrohistiocytoma-like pattern, two cases had mixed histologic patterns and the remaining case showed leiomyosarcoma-like histologic features. Immunohistochemically, the tumor cells expressed SMA (10/10),calponin (9/10),desmin (6/10) and CKpan (9/10). Cytoplasmic staining for ALK1 and ALK (5A4) was detected in 7 of 10 cases and 8 of 10 cases, respectively. Nuclear and cytoplasmic staining for ALK (D5F3) was detected in 7 of 10 cases. Among eight cases with material available for FISH analysis, ALK rearrangement was present in five cases. Follow-up data were available in eight patients and none had local recurrence nor distant metastasis.Conclusion:IMT of the urinary bladder is an uncommon mesenchymal neoplasm with intermediate malignant potential.It has special clinicopathologic features, and a minority of cases have local tumor recurrence.