[A case of spontaneous rupture of renal leiomyosarcoma].

A 53-year-old female visited our out-patient department complaining of right flank pain. Ultrasonography revealed a solid mass lesion in the lower pole of the right kidney and further evaluation was scheduled. A few days later, she suddenly felt pain at the abdominal enlarged mass. Computed tomographic (CT) scan revealed a huge retroperitoneal mass with heterogenous density. Spontaneous rupture of renal tumor was suspected and emergency nephrectomy was performed. The ruptured tumor was pale, elastic firm and invaded directly to the duodenum. Histopathological findings revealed fibrous cells with frequent nuclear mitosis. Smooth muscle actin was identified immunohistochemically. Therefore, the tumor was diagnosed as leiomyosarcoma. The patient died 2 months after operation due to perforation of the intestine.