COVID-19 Vaccination Induced Lymphadenopathy in a Specialized Breast Imaging Clinic in Israel: Analysis of 163 cases

Acad Radiol. 2021 Sep;28(9):1191-1197. doi: 10.1016/j.acra.2021.06.003. Epub 2021 Jun 10.


Introduction: Following vaccination of Israeli population with Pfizer-BioNTech COVID-19 Vaccine, an unusual increase in axillary-lymphadenopathy was noted. This study assesses the rate and magnitude of this trend from breast-imaging standpoint.

Materials and methods: Participants undergoing breast-imaging, in whom isolated axillary-lymphadenopathy was detected were questioned regarding SARS-CoV-2 vaccine to the ipsilateral arm. Patients' and imaging characteristics were statistically compared. In order to perform a very short-term follow-up, twelve healthy vaccinated medical staff-members, underwent axillary-ultrasound shortly after the second dose, and follow-up.

Results: Axillary-lymphadenopathy attributed to vaccination was found in 163 women undergoing breast-imaging, including BRCA-carriers. During the study, number of detected lymphadenopathies increased by 394% (p = 0.00001) in comparison with previous 2 consecutive years. Mean cortical-thickness of abnormal lymph-nodes after second dose vaccination was 5 ± 2 mm. Longer lymph-node diameter after second vaccination was noted (from 15 ± 5 mm, to 18 ± 6 mm, p = 0.005). In the subgroup of medical staff members, following trends were observed: in patients with positive antibodies, lymph-node cortical-thickness was larger than patients with negative serology (p = 0.03); lymph-node cortical-thickness decreased in 4-5 weeks follow-up (p = 0.007). Lymphadenopathy was evident on mammography in only 49% of cases.

Discussion: Vaccine-associated lymphadenopathy is an important phenomenon with great impact on breast-imaging clinic workload. Results suggest the appearance of cortical thickening shortly after both doses. Positive serology is associated with increased lymph-node cortical-thickness. In asymptomatic vaccinated women with ipsilateral axillary-lymphadenopathy as the only abnormal finding, radiological follow-up is probably not indicated. BRCA-carriers, although at higher risk for breast-cancer, should probably receive the same management as average-risk patients.

Keywords: BRCA-carriers; COVID-19 vaccine; SARS-Cov-2; axillary lymphadenopathy; breast imaging.

MeSH terms

  • Axilla
  • BNT162 Vaccine
  • Breast / diagnostic imaging*
  • COVID-19 Vaccines / adverse effects*
  • COVID-19* / prevention & control
  • Female
  • Humans
  • Israel / epidemiology
  • Lymph Nodes
  • Lymphadenopathy / chemically induced*
  • Lymphadenopathy / epidemiology
  • Vaccination / adverse effects


  • COVID-19 Vaccines
  • BNT162 Vaccine