Isolated breast parenchymal changes following COVID-19 vaccine booster

Ipsilateral transient axillary lymphadenopathy is well-documented following COVID-19 mRNA vaccine administration. Recently, rare mammographic findings of breast tissue changes with co-existing lymphadenopathy have been documented. Current literature on isolated ipsilateral true breast parenchymal changes on diagnostic mammography in symptomatic patients following COVID-19 mRNA vaccine administration is limited. This is one of the first case reports that demonstrates isolated ipsilateral focal asymmetry 5 days after administration of COVID-19 mRNA vaccine followed by complete resolution of symptoms and focal asymmetry confirmed on follow up magnetic resonance imaging. These findings warrant the development of guidelines to reduce unnecessary invasive procedures as part of the workup for possible malignancy.