Thymic Carcinoma With Endobronchial Metastasis: A Case Report
Thymic carcinoma is a rare cancer, accounting for only 1% to 4% of thymic epithelial tumors. Endobronchial metastasis is a rare presentation of these tumors. A 64-year-old man presented with a cough. Lung cancer was suspected because a chest radiograph showed a 7-cm mass in the left pulmonary hilum. Computed tomography showed a mass in the anterior mediastinum and an infiltrate in the upper lobe of the left lung. Bronchoscopy demonstrated bilateral polypoid tumors in the left B3 bronchus and the right B1 bronchus. Endobronchial biopsies of both lesions resulted in a diagnosis of squamous cell carcinoma that was positive for c-KIT by immunohistochemical staining. The patient was eventually found to have thymic squamous cell carcinoma with bilateral endobronchial metastases (stage IVb according to the Masaoka-Koga staging system) by diagnostic video-assisted thoracoscopic surgery. He was subsequently treated with platinum-doublet chemotherapy and achieved a partial response for 18.8 months.