Combined 18 F-FDG and 11 C-Methionine PET/CT scans in a case of metastatic hepatocellular carcinoma

A 37-year-old male who underwent a central hepatectomy of the liver for hepatocellular carcinoma (HCC) was referred for an 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) study to rule out tumor recurrence or metastases. The scan showed a recurrent hepatic mass at the operative site, along with low-grade uptake in bilateral pulmonary metastases, mediastinal and hilar lymph nodes, and few skeletal sites. A non-FDG avid intracranial extradural mass was visualized in the right frontal lobe. The 11 C-methionine PET/CT scan performed subsequently revealed a larger area of involvement at the primary site, along with widespread metastases to the lungs, mediastinal, hilar, and abdominal lymph nodes, and multiple skeletal sites. Further, dural metastasis with high tracer uptake was noted in the frontal region. To the best of our knowledge, this is the first case documented in the literature, wherein 11 C-methionine PET/CT played a significant role in delineating the widespread dissemination, including the extremely rare dural involvement in a case of HCC. This report highlights the potential value of 11 C-methionine PET/CT in assessing the hepatic and extrahepatic tumor burden in cases of HCC, especially in clinically unexpected locations.