FDG PET/CT diagnosis of hepatic lymphoma mimicking focal fatty infiltration on CT

摘要

Areas of hypoattenuation in the liver which do not have mass effect are typically thought to represent focal fatty infiltration. Rarely, tumors can present without mass effect in the liver. We present a case in which areas of liver hypoattenuation which were initially thought to represent focal fatty infiltration on CT due to lack of mass effect had abnormal uptake on a FDG PET/CT exam; these areas were due to secondary hepatic involvement from non-Hodgkin’s lymphoma. Keywords: Liver, Lymphoma, Positron Emission Tomography, PETCASE REPORTA 72-year old man presenting with anemia, abdominal pain, and nausea and vomiting underwent a contrast-enhanced computed tomography (CT) of the abdomen and pelvis which demonstrated a short segment of severe small bowel thickening. The patient also had two areas of hypodensity in the liver (Figs. 1,?,2)2) which were thought to represent focal fatty infiltration given the lack of mass effect. The CT was followed by a F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) exam (Figs 1–3) which demonstrated intense FDG uptake in the small bowel lesion and areas of liver hypodensity. The patient underwent resection of the small bowel lesion which was a large B-cell lymphoma and core biopsy of the liver (Fig. 4) which demonstrated metastatic lymphoma. This case demonstrates that hepatic lymphoma can present without mass-effect; this finding has not been well-described. FDG PET/CT can differentiate hepatic tumors without mass-effect from focal fatty infiltration. Open in a separate windowFigure 1 72-year old man with hepatic lymphoma mimicking focal fatty infiltration on CT. (A) Contrast-enhanced CT (General Electric Lightspeed VCT, kVp 120, mAs 433, 5 mm slice reconstruction) performed with 125 cc of Isovue-370 intravenous contrast demonstrates linear hypodensity (arrows) surrounding the middle hepatic vein. There is no mass-effect upon the vein. This was thought to represent focal fatty infiltration given the lack of mass-effect. However an axial fused image from a PET/CT (B) performed with 19.1 mCi of F-18 FDG imaged 60 minutes after injection demonstrates intense FDG uptake at this site.