[A case of leiomyosarcoma as a mediastinal tumor excised by bilateral thoracotomy].

Leiomyosarcoma as a mediastinal tumor is so rare that no more than 6 and 12 cases have so far been reported in and out Japan, respectively. The patient was 74-year-old male. While treated at the outpatient clinic of our university hospital for low back pain, he was referred to our department because of a shadow of the mediastinum on chest roentgenogram. A fist-sized tumor was found located in the posterior mediastinum behind the heart. Since it was difficult to make a preoperative definitive diagnosis, it was excised by bilateral thoracotomy. Histologically, it was compatible with sarcoma and a definitive diagnosis of leiomyosarcoma was made based on electron microscopic findings.