Axillary lymphadenopathy at the time of COVID-19 vaccination: ten recommendations from the European Society of Breast Imaging (EUSOBI)

Abstract

Unilateral axillary lymphadenopathy is a frequent mild side effect of COVID-19 vaccination. European Society of Breast Imaging (EUSOBI) proposes ten recommendations to standardise its management and reduce unnecessary additional imaging and invasive procedures: (1) in patients with previous history of breast cancer, vaccination should be performed in the contralateral arm or in the thigh; (2) collect vaccination data for all patients referred to breast imaging services, including patients undergoing breast cancer staging and follow-up imaging examinations; (3) perform breast imaging examinations preferentially before vaccination or at least 12 weeks after the last vaccine dose; (4) in patients with newly diagnosed breast cancer, apply standard imaging protocols regardless of vaccination status; (5) in any case of symptomatic or imaging-detected axillary lymphadenopathy before vaccination or at least 12 weeks after, examine with appropriate imaging the contralateral axilla and both breasts to exclude malignancy; (6) in case of axillary lymphadenopathy contralateral to the vaccination side, perform standard work-up; (7) in patients without breast cancer history and no suspicious breast imaging findings, lymphadenopathy only ipsilateral to the vaccination side within 12 weeks after vaccination can be considered benign or probably-benign, depending on clinical context; (8) in patients without breast cancer history, post-vaccination lymphadenopathy coupled with suspicious breast finding requires standard work-up, including biopsy when appropriate; (9) in patients with breast cancer history, interpret and manage post-vaccination lymphadenopathy considering the timeframe from vaccination and overall nodal metastatic risk; (10) complex or unclear cases should be managed by the multidisciplinary team.

Keywords: COVID-19 vaccines; Lymphadenopathy; Magnetic resonance imaging; Mammography; Ultrasonography (breast).

Fig. 1

Ultrasonography of the left axilla showing an enlarged 17 mm reactive lymph node in a 45-year-old woman about a week after receiving the first dose of the Vaxzevria COVID-19 vaccine. Note the asymmetrical cortical thickening (white arrow) associated with a well-represented central fatty hilum

Fig. 2

Screening mammography performed in a 44-year-old woman with a positive family history for breast cancer (mother and aunt), bearing implants for aesthetic purposes. Mammography (a) was considered negative. Breast ultrasonography was also performed because of her family history and high breast density (ACR category d). While ultrasonography was negative for both breasts, multiple round, enlarged, hypoechoic lymph nodes (measuring up to 1 cm in axial diameter), with a thickened (< 3 mm) cortex, were seen in the left axilla (b). There were no skin changes and there was no history of any infection or trauma. On the right side, axillary lymph nodes were normal. Because of her family history and the presence of breast implants, magnetic resonance imaging was performed (c T2-weighted short-time inversion recovery; d fat-sat contrast-enhanced T1-weighted gradient-echo; e apparent diffusion coefficient map). No suspicious mass or non-mass lesions were seen in both breasts. Implants showed no signs of rupture (not shown). In the left axilla, multiple enlarged lymph nodes were well visible in c and d (red circles); on the apparent diffusion coefficient map (e, red circle), they mainly exhibited low signal (restricted diffusivity). When an ultrasound-guided biopsy of the most suspicious lymph node was proposed, the patient mentioned that she had a Comirnaty COVID-19 vaccination one week before in the left arm. The attending radiologist was more than surprised to hear this, as at that time, a COVID-19 vaccination was only administered to people older than 70 years. Follow-up performed four weeks after the second vaccination was negative and showed no residual enlarged lymph nodes