The incidence and duration of COVID-19 vaccine-related reactive lymphadenopathy on 18F-FDG PET-CT

Clin Med (Lond). 2021 Nov;21(6):e633-e638. doi: 10.7861/clinmed.2021-0420.

Abstract

Objectives: Reactive axillary lymph nodes (ALN) may occur post-COVID-19 vaccination. This may be confused with malignant nodal metastases on oncological imaging. We aimed to determine the reactive ALN incidence and duration on 18F-fluorodeoxyglucose positron emission tomography - computed tomography (18F-FDG PET-CT), and its relationship with gender, age and vaccine type.

Methods: A retrospective study was performed. Two-hundred and four eligible patients had 18F-FDG PET-CT between 01 January 2021 and 31 March 2021, post-vaccination with Pfizer-BioNTech or Oxford-AstraZeneca vaccine. Image analysis was performed on dedicated workstations. SPSS was used for statistical analysis.

Results: Thirty-six per cent of patients had reactive ALN until 10 weeks post-vaccination; reducing in frequency and intensity with time. Women were more likely to have reactive ALN compared with men. The frequency and intensity were higher in patients aged <65 years compared with those aged ≥65 years. However, no difference was found between both vaccine types in our study cohort.

Conclusions: Physicians' awareness of COVID-19 vaccine-related reactive ALN on 18F-FDG PET-CT is important to avoid inappropriate upstaging of cancers.

Keywords: 18F-FDG PET-CT; COVID-19 vaccine; lymphadenopathy.

MeSH terms

  • COVID-19 Vaccines
  • COVID-19*
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Incidence
  • Lymphadenopathy* / diagnostic imaging
  • Lymphadenopathy* / epidemiology
  • Male
  • Positron Emission Tomography Computed Tomography
  • Positron-Emission Tomography
  • Retrospective Studies
  • SARS-CoV-2

Substances

  • COVID-19 Vaccines
  • Fluorodeoxyglucose F18