A 71-year-old man who had undergone surgical resection of esophageal gastrointestinal stromal tumors (GISTs) through a right posterolateral thoracotomy 8 years earlier was referred for treatment of an anterior mediastinal mass discovered on a follow-up chest radiograph in October 2007. Computed tomography findings revealed a tumor, 82 x 49 mm, with calcification, in the anterior mediastinum. When we radically resected the tumor via a median sternectomy, we found that it was actually located in the pleural cavity, and there was a small nodule near the main tumor on other pleura. Microscopically, the tumor was comprised of uniform spindle cells with fibrillary eosinophilic cytoplasm. In addition, immunostaining showed that the tumor was positive for CD117 (c-kit). The diagnosis was pleural dissemination of esophageal GISTs 8 years after primary surgery, making this the first report of pleural dissemination of esophageal GISTs after such a prolonged postsurgical interval.