Hypermetabolic Axillary Lymphadenopathy on FDG PET/CT Due to COVID-19 Vaccination

Aim: This study aimed to evaluate the incidence of hypermetabolic axillary lymph nodes due to COVID-19
vaccines and the factors affecting hypermetabolic axillary lymph nodes in F18-fluorodeoxyglucose (FDG)
positron emission tomography/computed tomography (PET/CT) in on cology patients.
Patients and Methods: Among the patients who underwent FDG PET/CT in our institution between
January 15, 2021, and June 15, 2021, those who received one or two doses of COVID-19 vaccine
(CoronaVac or Biontech) were included in the study. Presence and number of ipsilateral hypermetabolic
axillary lymph nodes, FDG uptake, and whether there was a difference between these data after the 1st
and 2nd vaccination were investigated.
Results: Unilateral hypermetabolic axillary lymph nodes was observed in 9.9% (18/182) of the patients
[9.6% (9/94) after 1st dose, 10.2% (9/88) after 2nd dose] vaccinated with CoronaVac; It was detected in
37.5% (9/24) of the patients [35% (7/20) after 1st dose, 50% (2/4) after 2nd dose] who vaccinated with
Biontech. A negative correlation was found between the presence of hypermetabolic axillary lymph nodes
and age in patients who vaccinated with CoronaV ac.
Conclusion: The frequency of hipermetabolik aksiller lenf nodu after CoronaVac was lower than that
observed after mRNA vaccines, a small group of patients in our study, and lower than reported in the
literature. However, the statistical difference could not be evaluated due to the insufficient number of
patients in the Biontech group. A brief history of vaccination is recommended before FDG PET/CT to
reduce false positives. The potential role of FDG PET/CT in comparing the efficacy of vaccines produced
with dif ferent biotechnologies should be searched in studies with large r patient populations.