New research offers radiologists guidance in differentiating between COVID vaccine-related swelling of the glands from malignant adenopathy based on specific features identified using ultrasound. 

Unilateral axillary adenopathy is a known side effect of COVID vaccines. The increased instances of axillary lymphadenopathy post-vaccine initially caused experts to advise women to delay their annual mammographic screenings, as many of them were having to undergo additional imaging and procedures to confirm that their swollen lymph nodes were benign. Research has since suggested that the adenopathy can sometimes persist for many months and that mammograms should not be delayed due to the COVID vaccine. 

Individuals who have abnormal lymph nodes identified on imaging are frequently sent for ultrasound. The modality is a valuable diagnostic tool when it comes to characterizing adenopathy, but experts note that there is some overlap between the appearance of benign and malignant nodes, which can make diagnosing their root causes challenging. 

With the number of individuals who are eligible to receive COVID vaccines and boosters continuing to rise, it is important to understand how lymph nodes with benign versus cancerous origins present on imaging. 

“Objectively differentiating benign from malignant adenopathy is of clinical value and can reduce costs and anxiety related to unnecessary biopsies and/or the need for follow-up examinations,” corresponding study author Chung HL, from the department of breast imaging at the University of Texas MD Anderson Cancer Center, and co-authors wrote.