B-mode and Doppler ultrasonography patterns of axillary and supraclavicular lymphadenopathy associated with mRNA COVID-19 vaccine.

In this study, we present the ultrasound imaging features of lymph nodes arising in the regional lymph node chain after the first or second dose of the Pfizer-BioNTech COVID-19 vaccine. Ipsilateral lymphadenopathy adjacent to the vaccine injection site is an extremely rare but expected adverse reaction following COVID-19 vaccination. Although axillary lymphadenopathy is more common, cases of supraclavicular lymphadenopathy have also been reported after widespread vaccination against COVID-19. Ultrasonography examinations were performed on seven patients with no previous pathological conditions, who presented to our radiology department after receiving the Pfizer-BioNTech COVID-19 vaccine. Bilateral axillary, supraclavicular and subclavicular lymph node stations were explored. These patients typically present with enlarged hypoechoic lymph nodes with the loss of fatty hilum, asymmetric or diffuse cortical thickening, and increased hilar and cortical vascularization on the color doppler ultrasonography of the ipsilateral axillary and supraclavicular regions. Radiologists and clinicians should be aware of the ultrasonographic features of these lymph nodes and should inform the patient that these lymph nodes are often a self-limiting process. Thus, unnecessary axillary lymph node biopsies should be avoided, and patients should be treated conservatively. [ABSTRACT FROM AUTHOR]