Axillary lymph nodes enlargement after Sars-CoV-2 vaccine in patients undergoing breast examination: a single-centre experience in 285 women

Purpose To assess the incidence of axillary lymphadenopathy over established time ranges after COVID-19 vaccination and lymph node pathologic features (i.e. size increase and qualitative characteristics) in subjects undergoing axillary evaluation during a breast imaging examination. Methods and materials The institutional review board approved this prospective study. Inclusion criteria: women undergoing mammography and breast ultrasound between July and October 2021; information about the COVID-19 vaccine and infection, if any. Exclusion criteria: known metastatic lymphadenopathy. Participants were divided into 5 subgroups according to time between vaccine and imaging: < 6 weeks; 7-8 weeks; 9-10 weeks; 11-12 weeks; > 12 weeks. Evaluation of axillary lymph nodes was performed with ultrasound. Descriptive statistical analysis was performed. p < 0.05 was considered significant. Results A total of 285 women were included. Most of the patients underwent Moderna vaccine (n = 175, 61.4%). 63/285 patients had a previous history of breast cancer (22.1%). 13/17 (76.5%) patients with previous COVID-19 infection had no previous history of cancer, whereas 4/17 had a previous history of cancer (p <.001). 41/285 (14.4%) women showed lymphadenopathy, and they were significantly younger (46.9 +/- 11.6 years) than women with borderline (54.0 +/- 11.9 years) or no lymphadenopathy (57.3 +/- 11.9 years) (p <.001). Lymphadenopathy and borderline lymphadenopathy were more frequently observed in the Moderna-vaccinated women and in the subgroup of patients evaluated < 6 weeks after vaccination (p < 0.001). The most common pathologic feature was cortical thickening, followed by complete or partial effacement of fatty hilum. Conclusion A lymphadenopathy within 12 weeks after vaccination is a common finding particularly in younger women and after Moderna vaccine and no further assessment should be required.

Automated summary

This study aimed to assess the incidence and pathologic features of axillary lymphadenopathy after COVID-19 vaccination. The results showed that lymphadenopathy was more common in younger women who received the Moderna vaccine. No further assessment is required for lymphadenopathy within 12 weeks after vaccination.