Document Type



Radiology; Radiation Oncology


Background: In the current era vaccine-associated lymphadenopathy (VAL) is not an uncommon presentation on 18F-FDG PET/CT examinations in patients inoculated with Coronavirus disease 2019 (COVID-19) vaccination. In this study, we are presenting data of VAL on 18F-FDG PET/CT regarding its prevalence, temporal response to vaccination and imaging characteristics of VAL.
Methods: Seventy-eight (78) consecutive vaccinated breast cancer (BC) patients who had 18FDG PET/CT were retrospectively analyzed. All patients had COVID-19 vaccine shots in contralateral arms and none in breast cancer site axilla (BSA). In 35 patients 18FDG avid nodes were found in vaccine site axilla (VSA). In 25 patients 18FDG avid nodes were found in BSA. Morphological criteria on CT images like size, presence of fatty hila and fat stranding of axillary nodes were analyzed. Metabolic criteria on PET images like SUVmax of nodes and liver as reference were also measured.
Results: Out of 78 patients, 35 had positive nodes in VSA (45% prevalence) and 25/78 had BSA (33% prevalence). Mean duration of COVID-19 vaccination in each group was 8 ±04 week (non-significant p-value). On CT images, 18FDG avid nodes in VSA were significantly smaller (10 ± 03 mm) and with intact fatty hila without fat stranding than nodes in BSA with loss of fatty hila (25 ±10 mm; p 2 SD of Hepatic SUVmax were subjected to ultrasound guided fine needle aspiration (FNA) and turned out to be metastatic in nature.
Conclusion: In COVID-19 vaccinated patients with BC, 18FDG avid nodes in VSA may pose diagnostic challenge. However, morphological (size < 10 mm short axis, intact fatty hila without fat stranding) and metabolic criteria (SUVmax 2 SD of hepatic SUVmax should be considered for FNA to rule out possible metastasis.

Publication (Name of Journal)

Asian Pacific Journal of Cancer Prevention