A 72 years old patient was referred to us with ileal adenocarcinoma after surgical desection. Fluorine-18- fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) imaging showed massive portal vein, tumor thrombosis. Clinical examination and laboratory tests did not support the diagnosis of septic thrombus. To the best of our knowledge, this is the first reported case in the literature of a massive tumor thrombus in the right portal system from ileal carcinoma, detected by (18)F-FDG PET/CT.