| Abstract: |
Hepatoma or hepatocellular carcinoma (HCC), a tumor arising from hepatocytes, is one of the most common tumors worldwide, with approximately one million new cases diagnosed/year. Five-year survival ranges from 70% for stage I to <20% for stage III. HCC is often associated with cirrhosis and chronic hepatitis. The tumor is staged using the AJCC TNM classification, which considers tumor size, vascular invasion, lymph node status, and metastatic disease. The tumor is usually advanced at the time of diagnosis. CT and MRI are usually used for staging used for this purpose. Several reports indicated low sensitivity of [18F]FDG for detecting HCC due to a relatively low [18F]FDG uptake within the tumor, due to the presence of glucose-6-phosphatase (G-6-Pase), an enzyme present in normal liver, which converts [18F]FDG-6-P to [18F]FDG, allowing the tracer to diffuse out of tumor cells. [18F]FDG-PET has clinical value for identifying distant metastases and identifying poorly differentiated HCC in patients with multiple lesions, since these lesions show higher [18F]FDG uptake. Cholangiocarcinoma is a neoplasm that arises from the cholangiocyte, the epithelial cells lining the bile ducts. It has an incidence of 1–2 per 100,000 in the western world. The majority of lesions are adenocarcinomas. The first clinical symptom is often painless jaundice. The role of [18F]FDG-PET/CT in these tumors is not clear, since the periductalin filtrating type may have minimal [18F]FDG uptake, while those that form masses concentrate [18F]FDG. Ampulla of Vater cancer and gallbladder carcinoma are usually associated with masses and are [18F]FDG positive. However, areas of cholangitis may cause false-positive findings. [18F]FDG-PET may have limited value for N staging due to difficulty in separating lymph node lesions from adjacent areas of the primary tumor. On the other hand, [18F]FDG-PET has a high diagnostic value for detecting distant lymph node involvement. © Springer Science+Business Media New York 2013. |
