Fig. 4

48-year-old woman with previous localization of melanoma on the left knee, who had been treated by TKI for 6 months. This patient received her first dose of COVID 19 vaccine in the right deltoid muscle (Pfizer-BioNtec Cominarty) 21 days prior to the PET examination. Multiple reactive nodes can be seen on the right axillae. Note that some of these nodes have benign CT patterns (bottom right panel: fatty hilum) while others may be considered suspicious based on CT appearance (top right panel: round shape, loss of the fatty hilum pattern). In this case, spread to the contralateral axilla from a leg primary without regional nodal or distant metastatic involvement should alert the reader to a low likelihood of malignancy