Thrombus or tumor?

Key clinical message: Contrast defects in veins are often diagnosed as benign thrombi, but depending on the patient's background it is necessary to differentiate between tumor thrombi. It is difficult to differentiate between these using contrast-enhanced CT alone, but with angioscopy it is easy to visually distinguish between a benign and tumor thrombi. Abstract: Contrast-enhanced computer tomography (CT) performed on a male patient being treated for de-differentiated chondrosarcoma revealed contrast defects in the pulmonary artery and right femoral vein, and a diagnosis of pulmonary artery thromboembolism and venous thromboembolism was made, and oral anticoagulant therapy was started. However, a follow-up CT showed that the contrast defect had extended to the inferior vena cava. Observation using an angioscope revealed that it was not a benign thrombi but a tumor.