Contrasting Molecular Imaging Findings in Hepatocellular Carcinoma Using Dual Positron Emission Tomography Modalities

Fibroblast activation protein (FAPI) has been recently incorporated as a molecular imaging radiotracer for the evaluation of epithelial neoplasms that support or complement the role of [¹⁸F]Fluorodeoxyglucose ([¹⁸F]FDG) in many cancer subtypes since its development. Both radiotracers have been shown to have diagnostic, prognostic, and predictive value for several neoplasms. Herein, we present a 73-year-old male patient with a complex medical and oncological history who was recently diagnosed with hepatocellular carcinoma (HCC). Both [¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI-04 revealed distinct molecular imaging characteristics. A large segment 8 hepatic mass was observed via [¹⁸F]FDG positron emission computed tomography (PET/CT), whereas [⁶⁸Ga]Ga-FAPI PET/CT revealed a large hepatic mass confined to segment 8, exhibiting complete photopenia. Overall, T2N0M0 stage II HCC disease was affirmed. The patient underwent two rounds of transarterial chemoembolization, which resulted in partial disease control and symptomatic control. To our knowledge, this case represents the first imaging instance to capture such unique molecular characteristics of HCC via a dual PET/CT approach composed of [¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI radiotracers.