18F-Fluciclovine Avid Axillary Lymph Nodes After COVID-19 Vaccination on PET/CT for Suspected Recurrence of Prostate Cancer

Abstract

Abnormal increased FDG avidity of axillary lymph nodes has become a frequent diagnostic dilemma on PET/CT in the current climate of global vaccinations directed against SARS-CoV-2. This is due to the inflammatory response evoked by vaccines and the non-specific nature of F18-Fludeoxyglucose (FDG), which includes increased uptake in both malignant and inflammatory processes. Similarly, F18-Fluciclovine (Axumin), an amino acid analog indicated for the assessment of biochemical recurrence of prostate cancer, may also demonstrate non-specific inflammatory uptake. We report a case of 18F-Fluciclovine PET/CT obtained for concern of prostate cancer which demonstrated isolated avid lymph nodes in the left axilla. Screening questionnaire revealed that the patient had received the second dose of the Pfizer-BioNTech COVID-19 Vaccine in his left shoulder recently and hence the uptake was determined to be reactive.