Introduction
Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor tends to be locally invasive or recurrent and rarely metastasizes. Originally described in the lung, and now has been reported at multiple extrapulmonary sites, particularly shows a preference to visceral soft tissue in children and young people.1 IMT of the urinary system occurs mostly in the bladder. However, kidney IMT represents a challenging diagnostic entity due to its nonspecific clinical presentation, laboratory findings, and most importantly radiologic findings.2 It is especially difficult to distinguish renal IMT from malignant tumor before surgery in children.3 Therefore, the awareness of its existence and deep understanding of its clinical and imaging characteristics are essential to avoid misdiagnosis and to provide better management. Despite the uncertain biological behavior of IMT, most patients get a favorable prognosis after surgery.4Herein, we report an IMT in a 6-year-old boy that was misdiagnosed as Wilms’ tumor. Written informed consent for academic use of his information was obtained from the children’s parents.