Liposarcoma arising from the right renal sinus with inferior vena caval involvement

A woman aged 55 was introduced to our medical center for retroperitoneal tumor incidentally discovered by screening computerized tomography. Imaging showed a round fatty tumor extending into the right kidney and infiltrating into the inferior vena cava and no distant metastasis. We extirpated the tumor and tumor thrombus infiltrating the inferior vena cava along with the right kidney en bloc. Pathological examination showed well-differentiated liposarcoma that we believe had arisen from the renal sinus. Liposarcoma arising from the renal sinus with intravenous involvement is distinctly rare. Treatment by complete resection is recommended.