Inflammatory myofibroblastic tumor (IMT) is a rare, mesenchymal tumor that has an increased incidence in childhood. Tumors are usually isolated to the chest, abdomen, and retroperitoneum, but metastatic presentations can be seen. Presenting symptoms are nonspecific and include fever, weight loss, pain, shortness of breath, and cough. Approximately 85% of IMTs harbor actionable kinase fusions. The diagnosis can be delayed because of overlapping features with inflammatory disorders, such as elevated inflammatory markers, increased immunoglobin G levels, fever, weight loss, and morphologic similarity with nonmalignant conditions. We present a girl aged 11 years with a TFG-ROS1 fusion-positive tumor of the lung that was initially diagnosed as an immunoglobin G4-related inflammatory pseudotumor. She underwent complete left-sided pneumonectomy and later recurred with widely metastatic disease. We then report the case of a boy aged 9 years with widely metastatic TFG-ROS1 fusion-positive IMT with rapid molecular diagnosis. In both children, there was an excellent response to oral targeted therapy. These cases reveal that rapid molecular testing of inflammatory tumors is not only important for diagnosis but also reveals therapeutic opportunities. Targeted inhibitors produce significant radiologic responses, enabling potentially curative treatment approaches for metastatic ROS1 fusion IMT with previously limited treatment options. Primary care pediatricians and pediatric subspecialists have a crucial role in the early consultation of a pediatric oncology center experienced in molecular diagnostics to facilitate a comprehensive evaluation for children with inflammatory tumors.

中文翻译：

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炎症性肿瘤的分子特征促进有效治疗的启动。

炎性肌纤维母细胞瘤 (IMT) 是一种罕见的间充质肿瘤，在儿童期发病率增加。肿瘤通常孤立于胸部、腹部和腹膜后，但可以看到转移性表现。出现的症状是非特异性的，包括发烧、体重减轻、疼痛、呼吸急促和咳嗽。大约 85% 的 IMT 具有可操作的激酶融合。由于与炎症性疾病的重叠特征，例如炎症标志物升高、免疫球蛋白 G 水平升高、发热、体重减轻以及与非恶性疾病的形态学相似，诊断可能会延迟。我们介绍了一名 11 岁女孩，患有 TFG-ROS1 融合阳性肺肿瘤，最初被诊断为免疫球蛋白 G4 相关炎性假瘤。她接受了完整的左侧全肺切除术，后来复发了广泛的转移性疾病。然后我们报告了一名 9 岁男孩的病例，该男孩患有广泛转移的 TFG-ROS1 融合阳性 IMT，并进行了快速分子诊断。在这两个孩子中，口服靶向治疗都有很好的反应。这些病例表明，炎症性肿瘤的快速分子检测不仅对诊断很重要，而且还揭示了治疗机会。靶向抑制剂产生显着的放射学反应，使以前有限的治疗选择为转移性 ROS1 融合 IMT 提供潜在的治愈性治疗方法。