Renal leiomyosarcoma.

Leiomyosarcoma (LMS) is a rare malignant tumor of smooth muscle origin that generally stems from soft tissues and uterine tissue. Although, a small percentage of these may originate from the smooth muscle or vessel walls, most of which are of venous origin. Renal leiomyosarcomas may arise from the smooth muscle fibers of renal pelvis, renal capsule or renal vessels, last one is the most frequent. We report a case of renal LMS that could be originated in the renal capsule.