Published online Jul 21, 2013. doi: 10.3748/wjg.v19.i27.4432
Revised: May 15, 2013
Accepted: June 1, 2013
Published online: July 21, 2013
Positron emission tomography (PET) using 18F-fluorodeoxyglucose (18F-FDG) is an imaging modality which reflects cellular glucose metabolism. Most malignant cells accumulate and trap 18F-FDG, allowing the visualisation of increased uptake. It is hence widely used to differentiate malignant from benign lesions. “False positive” findings of hepatic lesions have been described in certain instances such as hepatic abscesses, but are rare in cases involving hepatocellular adenomas. To our knowledge, there have been only 7 reports in the English literature documenting PET-avid hepatocellular adenomas; 6 of the 7 reports were published in the last 3 years with the first report by Patel et al. We report the case of a 44-year-old Chinese female patient with a history of cervical adenocarcinoma, referred for a hepatic lesion noted on a surveillance computed tomography (CT) scan. A subsequent CT-PET performed showed a hypermetabolic lesion (standardized uptake value 7.9) in segment IVb of the liver. After discussion at a multi-disciplinary hepato-pancreato-biliary conference, the consensus was that of a metastatic lesion from her previous cervical adenocarcinoma, and a resection of the hepatic lesion was performed. Histology revealed features consistent with a hepatocyte nuclear factor-1 α inactivated steatotic hepatocellular adenoma.
Core tip: This case illustrates a unique example of a false-positive finding on the computed tomography- positron emission tomography (CT-PET) due to a hepatic adenoma mimicking a metastatic lesion in the liver. It serves to highlight that not all CT-PET findings are associated with malignancy. In equivocal cases where CT-PET findings are discordant with other imaging modalities and/or clinical/biochemical features, further evaluation with different imaging modalities or novel PET tracers may be considered. This is especially pertinent in this day and age, where the PET scan is widely used in clinical practise to differentiate benign from malignant lesions, as well as a modality in cancer surveillance and staging.