Radiologists across the country are noticing a potential side effect of the COVID-19 vaccine: swelling of the lymph nodes under the armpit that appear on mammograms.
Lymph nodes exist in various regions around the body, including the neck, groin, and armpits, and swell in the presence of bacteria, infection, or sometimes cancer, according to the Mayo Clinic.
Usually, an enlarged lymph node in the armpit region would warrant a breast tissue biopsy, as it may be an indicator of breast cancer starting to spread, according to the Susan G. Komen Foundation; however, radiologists say that these events after COVID-19 vaccine are expected and are not normally of concern.
In most patients, evidence of swollen lymph nodes from vaccination does not usually warrant additional action unless swelling persists or other health problems are at stake, Massachusetts General Hospital said in a recent statement.
The Centers for Disease Control and Prevention said in its reports on the Moderna and Pfizer vaccine that swollen lymph nodes were “plausibly related to the vaccine” and were most often seen in the arms and neck regions two to four days after vaccination . The swelling tended to last on average one to two days for Moderna and about 10 days for Pfizer.
Massachusetts General Hospital has warned that radiologists are likely to see an increase in the number of enlarged lymph nodes that appear during mammograms as nationwide vaccination efforts increase.
Constance Lehman, head of breast imaging at Massachusetts General Hospital, told The New York Times that she was happy to spread the word to help people feel at ease.
I am especially eager to speak to all patients undergoing surveillance after successful previous cancer treatment, she said.