[Mediastinal granular cell tumor arising from the left recurrent nerve; report of a case].

Granular cell tumor is found in various organs but is rare in the mediastinum. We report a case of 36-year-old woman with a granular cell tumor in the left upper mediastinum. She was admitted to our hospital because of hoarseness. Laryngoscopic examination revealed left vocal cord paralysis. Chest computed tomography (CT) showed a 3.0 x 2.0 cm well circumscribed tumor at the left side of the trachea in the left upper mediastinum. As hoarseness was suspected to be attributable to the mediastinal tumor, tumor resection was performed. It was found that the tumor involved the left recurrent nerve. The tumor was completely excised with combined resection of the left recurrent nerve. Histopathologically, the tumor consisted of cells with eosinophilic granules and S-100 protein positive materials in the cytoplasm, and diagnosed a granular cell tumor.