Thymic and Mediastinal Lymph Node Metastasis of Colon Cancer

Most anterior mediastinal tumors are thymomas. Thymic metastasis from other primary cancers is extremely rare. We report the case of a 72-year-old man who developed thymic and mediastinal lymph node metastases of cecum cancer. He had undergone laparoscopic ileocecal resection with regional lymph node dissection for primary cecum cancer 15 months previously. Follow-up computed tomography revealed tumors in the anterior mediastinum. Fluorodeoxyglucose positron emission tomography showed positive uptake in the tumors. Because thymoma or thymic carcinoma was suspected, we performed total thymectomy via a median sternotomy. Histologic findings of the anterior mediastinal tumors were compatible with metastasis of the previously resected cecum cancer.