Fibrolamellar HCC: A case based pictorial review highlighting the role of 18F-FDG PET CT with multimodality comparison.

1188 Purpose: 18 F- fluorodeoxyglucose (18F-FDG) PET-CT has proven to be invaluable tool in the initial diagnosis, staging, and restaging of a variety of cancers. The potential use of 18F-FDG PET CT in the evaluation and management of hepatocellular carcinoma (HCC) continues to evolve over last two decades. However, the role of F-18 FDG PET in fibrolamellar (FL) HCC has not been fully evaluated. It is assumed that the overall uptake of F-18 FDG in HCC correlates to the degree of tumor differentiation with more uptake in dedifferentiated, highly malignant lesions. FL-HCC is a distinct but less common HCC variant, occurring in younger patients with non-cirrhotic liver. The purpose of this case based pictorial review is to highlight the evolving role of 18F FDG-PET for the staging (both initial and re-staging) of FL-HCC and detection of intrahepatic, loco regional and distant metastasis. Methods: Patient with known diagnosis of fibrolamellar HCC referred to our institution for initial and posttreatment staging over a period of 3 years (Jan 2017- Dec 2019) with 18F FDG PET/CT scans were identified and retrospectively reviewed. A total of 13 patients were reviewed. Correlation with other imaging modalities like CT and MRI was also performed. Results: F-18 FDG PET CT clearly demonstrated utility in initial and restaging of patients with fibrolamellar HCC. Out of the 13 patients (8 female and 5 male) F-18 FDG PET CT identified hepatic (local), loco-regional (hepatic and peri-hepatic nodes) and distant metastasis on both initial and restaging scans. Majority of the hepatic lesions demonstrated FDG avidity only slightly greater than the hepatic background SUV max; while nodal and distant metastasis showed moderately increased FDG avidity. Only one patient had hepatic lesions with FDG avidity same as that of normal hepatic background. Conclusions: This case based multi-modality pictorial review highlights the significant evolving role and utility of 18F-FDG PET CT in the management of fibrolamellar HCC.