[Invasive Thymoma with Unexpected Pleural Dissemination Completely Resected Under 4K Three-dimensional Endoscopy:Report of a Case].

According to the guidelines for thymic tumors, surgical resection is recommended for clinical stage Ⅳ thymic epithelial tumors if completely resectable. A 38-year-old woman presented with fever, chest pain, and back pain. Computed tomography (CT) revealed a mediastinal tumor, which was diagnosed as thymoma type B3 through CT-guided biopsy. Intraoperatively, using 4K three-dimensional (3D) endoscopy, tumor invasion into the left upper lobe and pleural dissemination on the parietal pleura and diaphragm were observed. To preserve the possibility of future re-resection, operation was thoracoscopically performed and the tumor was removed, including partial resection of the left upper lobe. All visible pleural dissemination lesions were also resected, including part of the left diaphragm. The diaphragmatic defect was reconstructed using a Gore-Tex Patch. There is no established treatment strategy for thymoma with incidental pleural dissemination, and the 4K 3D endoscopy may contribute to the successful completion of such a complex operation.