False-positive FDG PET/CT due to liver parenchymal injury caused by a surgical retractor.

A 70-year-old man underwent partial gastrectomy with pathology demonstrating gastric follicular lymphoma. After surgery, a staging FDG PET/CT study demonstrated an FDG-avid low-attenuation band in the liver. Corresponding MRI demonstrated a high T2 signal abnormality. This was believed to represent liver parenchymal injury due to liver retraction during surgery. The patient was managed conservatively. MRI at 1 month of follow-up demonstrated resolution of the T2 signal abnormality. FDG PET/CT at 6 months of follow-up demonstrated resolution of FDG uptake. Tissue injury from surgical retraction can produce FDG-avid lesions that need to be distinguished from malignancy on PET/CT.