Fluorodeoxyglucose uptake in absence of CT abnormality on PET-CT: What is it?

Figure 3 Axillary uptake. A 63-year-old man with history of bladder cancer had fluorodeoxyglucose (FDG) positron emission tomography-computer tomography (PET-CT) for restaging. Axial PET image of the upper chest shows focal uptake in the left axilla (arrow). Corresponding to this focus, there is a small benign lymph node with fat lumen on CT (arrow). The uptake is secondary to infiltration of injected FDG at the antecubital site.