目的观察婴幼儿炎症性肌纤维母细胞肿瘤(IMT)的临床病理特征、免疫表型,探讨婴幼儿IMT的诊断、鉴别诊断、治疗及预后。方法收集5例婴幼儿IMT,分析其临床病理特征、免疫表型并随访。结果患儿5例,男1例,女4例,年龄8~22个月,中位年龄14个月。发生于肺部2例,腹腔3例。镜下表现为胖梭形纤维母细胞/肌纤维母细胞增生,呈束状或旋涡状排列,间质内伴有数量不等的炎细胞浸润,主要为成熟的浆细胞、淋巴细胞和嗜酸性粒细胞。肿瘤细胞排列疏松或致密,2例均可见体积较大的神经节样细胞。免疫组化:3例ALK胞质(+),2例(-)。随访3例ALK阳性病例中2例复发,1例失访。2例ALK阴性病例无复发。结论 IMT是一种少见的中间型肿瘤,好发于儿童,婴幼儿期罕见,需与其它梭形细胞肿瘤鉴别,该瘤具有复发潜能,偶可转移,术后需密切随访观察。 Objective To observe the clinicopathological features and immunophenotype of inflammatory myofibroblastic tumor (IMT) in infants and young children, and to explore the diagnosis, differential diagnosis, treatment and prognosis of infants and young children with IMT. Methods 5 cases of infants and young children were collected IMT, analysis of its clinical and pathological features, immunophenotype and follow-up. Results There were 5 cases of children, 1 males and 4 females, aged from 8 to 22 months, with a median age of 14 months. Occurred in the lungs in 2 cases, 3 cases of abdominal cavity. Microscopically, fat spindle fibroblasts / myofibroblasts were hyperplastic, arranged in a bundle or swirling pattern, interstitial with a varying number of inflammatory cell infiltration, mainly of mature plasma cells, lymphocytes and eosinophils cell. Tumor cells arranged in a loose or dense, large volume of ganglion cells can be seen in 2 cases. Immunohistochemistry: 3 cases of ALK cytoplasm (+), 2 cases (-). Two cases of ALK positive cases were followed up, and one case was lost. Two cases of ALK negative cases without recurrence. Conclusion IMT is a rare intermediate tumor that occurs in children. It is rare in infancy. It needs to be differentiated from other spindle cell tumors. The tumor has the potential of recurrence and can be metastasized even after follow-up.