Inflammatory Myofibroblastic Tumor of the Urinary System on Computed Tomography at a High-Volume Institution in China

Objective: Inflammatory myofibroblastic tumors (IMTs) of the urinary system are relatively rare and often misdiagnosed. We aimed to summarize and analyze the clinical manifestations, imaging features, management, and follow-up of renal and bladder IMTs. Methods: In this retrospective study, 22 patients with IMT pathologically verified between 2009 and 2018 were included. Epidemiologic, clinical, pathologic, and imaging findings were recorded. Tumor size, location, and shape were analyzed and summarized. Results: There were 22 patients with a median age of 45 years (range: 20-74), including 14 patients with renal IMT and 8 patients with bladder IMT, who met the eligibility criteria. In 21 patients, IMT appeared as a single lesion, whereas 1 patient showed bilateral renal lesions. Surgical resection was the sole therapy, and follow-up information was acquired from 13 individuals with no evidence of recurrence or metastasis. In our study, a slightly hypodense or isodense homogeneous tumor with a clear boundary was more often seen. On contrast-enhanced computed tomography (CT), they were often manifesting as a slightly heterogeneous enhancement. Conclusions: The nature of IMTs might cause a lack of generalizability. However, it will be useful to know that there are various CT demonstrations of IMTs. CT images are useful for the detection, location, and characterization of urinary IMTs, which can help in better clinical decision-making and can also be an optimal imaging technique for follow-up.