FDG PET/CT in the liver: lesions mimicking malignancies.
OBJECTIVE
18F-fluorodeoxyglucose (FDG) PET/CT is invaluable in managing liver lesions, in particular in the evaluation of suspected liver metastases. It is both sensitive and specific in detecting liver metastases from a wide range of primary cancers, and may change clinical management, most commonly by detecting additional lesions and decreasing the number of futile surgeries. However, some benign lesions may also show increased metabolic activity which can lead to false positive PET findings. We describe some of these lesions and their imaging characteristics that may help in differentiating them from malignant metastases.


METHODS
e reviewed all whole body FDG PET/CT studies performed over a 5-year period in our institution, and identified those with focal liver lesions showing increased FDG uptake for which histological results were available.


RESULTS
majority of lesions showing increased metabolic activity were due to malignant disease, such as metastases or primary liver tumours. However, we also found increased FDG uptake in non-neoplastic lesions such as Cryptococcosis, abscesses, and secondary inflammation from cholecystitis. Increased metabolic activity was also seen in some benign neoplasms such as hepatic adenomas and hemangioendotheliomas.


CONCLUSIONS
DG PET/CT is currently the most sensitive non-invasive imaging modality for the detection of hepatic metastases, particularly from the gastrointestinal tract. False positive results are rare, and have been described mainly in abscesses. However, other lesions can also show increased metabolic activity, and failure to differentiate these from metastases may result in inappropriate treatment.
Gerald Jit Shen
GJ
Tan
Salvatore Ugo
SU
Berlangieri
Sze Ting
ST
Lee
Andrew Mark
AM
Scott
D000236:Adenoma / Q000175:diagnosis; D003453:Cryptococcosis / Q000175:diagnosis; D019788:Fluorodeoxyglucose F18; D006390:Hemangioendothelioma / Q000175:diagnosis; D006801:Humans; D008099:Liver / Q000378:metabolism; D008100:Liver Abscess / Q000175:diagnosis; D008107:Liver Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism; D008113:Liver Neoplasms / Q000175:diagnosis*; D049268:Positron-Emission Tomography; D011859:Radiography; D019275:Radiopharmaceuticals; D051598:Whole Body Imaging
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18