Extensive tumor thrombus of hepatocellular carcinoma in the entire portal venous system detected on fluorodeoxyglucose positron emission tomography computed tomography
A 50-years-old male, a case of hepatocellular carcinoma (HCC) was referred for a fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT) scan for a pre trans arterial radio embolization (TARE) evaluation. He was positive for hepatitis B virus infection. His alpha feto-protien levels were significantly elevated at 34,700.50 ng/ml (normal values 0-15 ng/ml). His scan revealed a moderately hypermetabolic mass in the right lobe of liver, which was the site of the primary HCC. In addition to the primary mass there was extensive hypermetabolic thrombus involving the portal vein and its branches, the splenic vein and the superior mesenteric vein. The maximum intensity projection image shows hypermetabolic thrombus involving the right and left branches of the portal vein (thin arrows), the main portal vein (block arrow), splenic (arrow head) and superior mesenteric (curved arrow) veins []. The CT images show a filling defect completely occluding the lumen of the right and left portal veins and the main portal vein. All these vessels were expanded and were enhancing when compared with the plain baseline images. The mass in the right lobe of liver directly invades the portal vein branches and shows attenuation characteristics same as that of the tumor [, left panel]. The fused PET CT image shows the hypermetabolic tumor thrombus in the branches of portal and in the main portal vein [, right panel]. Hypermetabolic filling defects were also seen in superior mesenteric vein [, upper panel] and splenic vein [, lower panel]. These characteristics of an expanded filling defect in the vessels, enhancing on post contrast images with intense FDG avidity and more over being directly invaded by the tumor itself led to the diagnosis of tumor thrombus over a bland thrombus. Though the patient was referred for a pre TARE evaluation, with such large tumor with extensive malignant thrombus, the patient opted against any invasive treatment option and the patient was put on oral Tyrosine kinase inhibitor.