A Case of Mediastinal Granular Cell Tumor with Horner's Syndrome.

Granular cell tumor (GCT) is found in various organs but is rare in the mediastinum. We report a case of mediastinal GCT in a 19-year-old woman who presented with left ptosis and miosis. CT and MRI revealed a 29-mm well-circumscribed tumor located close to the first thoracic vertebra with features suggesting a neurogenic tumor. The tumor was completely excised using single-port video-assisted thoracoscopic surgery. Histopathological and immunohistochemical analysis revealed that the tumor was a benign GCT. Postoperatively, left ptosis and miosis had improved slightly. To our knowledge, this is the first report regarding mediastinal GCT presenting with preoperative Horner's syndrome.