COVID-19 vaccination-related [18F]FDG-avid lymph node in a patient with marginal zone B-cell lymphoma.

The [18F]FDG PET/CT is a crucial tool in the diagnostic process and monitoring of neoplastic diseases. Currently, during the global program of vaccination against COVID-19 and the possibility of axillary lymphadenopathy after this injection, the correct interpretation of PET/CT images is vitally significant and may create some difficulties. We present a case of increased uptake of [18F]FDG in an axillary lymph node in a PET/CT scan performed 2 days after the Pfizer BioNTech COVID-19 vaccine in a 48-year-old patient newly diagnosed with marginal zone B-cell lymphoma.