[Misdiagnosis of a Leiomyosarcoma of the inferior vena cava as a renal cell carcinoma].

Leiomyosarcoma of the vena cava inferior (VCI) is a rare mesenchymal malignant tumor of the retroperitoneum. About 200 cases have been described in the literature so far. Leiomyosarcomas may resemble other tumors including renal cell carcinoma, adrenal carcinoma, and hepatic adenoma. Thus, misinterpretation of a leiomyosarcoma of the VCI is a common problem. We present a 71-year-old female with a large subhepatic, retroperitoneal tumorous mass which was diagnosed to be a renal cell carcinoma by sonography and computed tomography. After application of magnetic resonance imaging and retrospective analysis of the CT scan, diagnosis could be revised. Laparotomy and en bloc resection of the tumor was performed; histopathological examination confirmed a leiomyosarcoma of the VCI. The postoperative course was unremarkable. Leiomyosarcoma of the VCI may resemble advanced stages of renal cell carcinoma. High-resolution imaging modalities (computed tomography, magnetic resonance imaging) are able to precisely evaluate the typical imaging characteristics of leiomyosarcomas, thus determining correct diagnosis in affected patients. This is essential for successful operative therapy.