A 49-year-old man complaining of nausea and vomiting was admitted to our hospital for the examinations. Blood tests demonstrated anemia due to iron deficiency and slightly elevated D-dimer. Colonoscopy defected early stage sigmoid colon cancer. Enhanced systemic computed tomography revealed that a 5-cm-long mass was growing along the descending aortic lumen and that multi-embolism had occurred in the peripheral arteries. The limited graft replacement of the descending aorta was carried out under cardiopulmonary bypass to prevent recurrent embolism. Histologically, the mass was a blood clot. In addition, the thickened endothelial lining and slight atheromatous degeneration was detected in the resected aortic wall. The patient was discharged after endoscopic mucosal resection for the sigmoid colon cancer. During the two-year follow-up period, despite no anticoagulation, the patient has developed no thrombus in the aorta and suffered no embolic events.