[A case of adult Wilms' tumor with vena caval involvement].

The patient was a 35-year-old female with the chief complaint of macrohematuria. Computerized tomographic (CT) scan, ultrasonography and magnetic resonance imaging (MRI) revealed the presence of a large and inhomogeneous mass in the left kidney, and a tumor thrombus growing in the inferior vena cava. Angiography also showed a hypervascular tumor in the left kidney. The chest X-ray and CT scan demonstrated multiple metastatic lesions in the bilateral lungs. Radical nephrectomy and thrombectomy was performed under the diagnosis of left renal tumor with its invasion of inferior vena cava. Pathological findings revealed that this tumor was nephroblastoma, and its type was clear cell sarcoma of the kidney (CCSK). The patient received chemotherapy according to National Wilms' Tumor Study (NWTS) IV chemotherapeutic drug regimen. In general, CCSK is known to have poor prognosis. However, doxorubicin has been reported to have a relatively good antitumor effect for CCSK. However, in this case, the evaluation after the first course of chemotherapy was progressive disease, because some new lesions appeared, although most old pulmonary metastatic lesions were reduced.