[A case of leiomyoma of the posterior mediastinum].

Leiomyoma of the mediastinum is rare and only 10 cases have been reported in Japan. A 57-year-old woman was admitted to our hospital complaining of dyspnea. Roentgenogram, CT scan and MRI of the chest showed a large mass with well defined margins occupying the posterior mediastinum. With the biopsy neurinoma was suspected and thoracotomy was performed which revealed the mass was not encapsulated and not related to the vagus, esophagus, bronchus, aorta, pulmonary veins. Only the mass was dissected carefully and removed. The operative findings and histology diagnosed it leiomyoma from unknown origin. But we suspected the tumor of originating from the small blood vessels, because they were surrounded with the spindle tumor cells.