Leiomyosarcoma of ovarian vein compression as a cause of hydronephrosis

We present a case of leiomyosarcoma of the right ovarian vein with MRI findings. The patient was a 52-year-old woman who had suffered from right flank pain for one week. Abdominal ultrasound and excretory urography revealed hydronephrosis of the right kidney. Ureteroscopy showed external compression at the right upper third of the ureter. CT and MRI of the abdomen revealed a retroperitoneal mass with compression of the right ureter. The retroperitoneal mass proved on histology to be a leiomyosarcoma arising from the right ovarian vein.