Tumor thrombus in the inferior vena cava from colon cancer detected by 18F-FDG-PET

We present a case of inferior vena cava (IVC) tumor thrombus detected by fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET). A man underwent operations for the treatment of sigmoid colon cancer at the age of 63. Because tumor markers [carcinoembryonic antigen (CEA) and CA19-9] were increased at the age of 67, abdominal contrast-enhanced computed tomography (CT) was performed. CT revealed IVC dilatation, including a low-attenuation area. 18F-FDG-PET was performed to make the differential diagnosis between tumor thrombus and clot. 18F-FDG-PET showed that 18F-FDG had accumulated in the IVC region. We considered the IVC tumor thrombus because of the 18F-FDG uptake in the IVC region and the patient's clinical course. To our knowledge, there are a few reports concerning 18F-FDG-PET and IVC tumor thrombus. 18F-FDG-PET may be useful in diagnosing tumor thrombus.