Inflammatory myofibroblastic tumor of the kidney in patient with nephron-sparing surgery. Case report and review of the literature.

According to the WHO classification, mesenchymal tumors of the kidney are divided into mesenchymal tumors occurring mainly in adults and children. Accumulating evidence suggests that renal mesenchymal tumors represent a group of histologically heterogeneous diseases. We are reporting the case of a 58-year-old man with a history of nephron-sparing surgery due to renal cell carcinoma in 2014 in his left kidney. He was urgently admitted to the hospital due to left-sided nephrotoxic and anuria. Computed tomography (CT) imaging was performed and revealed irregular tumor mass. He underwent left-sided nephrectomy. Microscopic appearance and immunoprofile allowed to diagnose the tumor as an inflammatory myofibroblastic tumor (IMT) of the kidney. According to the 2016 World Health Organization (WHO) classification of tumors of the urinary system and male genital organs, IMT is a benign mesenchymal tumor with malignant potential. Typical locations are the liver and biliary tract, lung, and gastrointestinal tract. In the urogenital system, IMT occurs mainly in the bladder. So far, 48 cases have been reported in the kidney.