[LEIOMYOSARCOMA ARISING FROM THE RENAL VEIN].

A 47-year-old female presented to a clinic complaining of right back pain. A CT scan revealed a right retroperitoneal mass and she was referred to our department for further evaluation. Contrast-enhanced CT and MRI revealed a right retroperitoneal mass (6 cm) in the hilum of the right kidney that invaded the right renal vein and inferior vena cava (IVC). Suspecting a tumor arising from retroperitoneal tissues involving the right renal vein and IVC, the decision was made to excise the tumor with the right kidney, renal vein, and a portion of the IVC. The histologic findings indicated that the tumor was a leiomyosarcoma originating from the renal vein wall. The tumor cells were spindle-shaped and stained positive for desmin, caldesmon and HHF35. The post-operative course was uneventful and she was recurrence-free 20 months after surgery. In addition to presenting a case of a leiomyosarcoma of the renal vein, a short review of the literature is provided.