Syracuse, NY – Earlier this year, the medical imaging department at Crouse Hospital began to notice an increase in lymph nodes in patients’ armpits during routine breast exams.
This is usually a cause for concern.
“An enlarged lymph node can be a signal for cancer,” said Dr. David Wang, Crouse’s medical director for breast imaging. “But an enlarged lymph node can also be seen with infection or any inflammatory process going on.
Spurred on by similar reports circulating among other radiologists, Crouse’s technicians began asking patients: “Have you had a vaccine against Covid-19 recently? Which arm? “
Bingo.
Swollen lymph nodes turned out to be a relatively common side effect of Covid vaccines, such as fever, chills and fatigue. Instead of the first stop of the metastatic cancer cells, the enlarged nodules simply revealed that the lymphatic system was doing its job as part of the body’s immune arsenal, mobilizing to fight the new coronavirus.
“This is really a typical reaction,” said Wang. “The side that leads to the injection is the side where the lymph nodes are enlarged. The other side looks totally normal. “
Wang and his team saw it for themselves: all five members of the imaging department found that they had a slight swelling of the lymph nodes after vaccinations, always under the arm that received the injection.
Wang said his size increased after the second dose of the Moderna vaccine, which he received about eight weeks ago. The knot has steadily lessened, he said.
The reaction is common in men and women, he said, and can be detected not only on mammograms and breast ultrasounds, but also on MRIs and CT scans. The magnification may vary. The lymph nodes are usually about a quarter to a half inch in length, but they can double in size when fighting an infection or reacting to the vaccine.
Crouse added a section to his paperwork asking patients if they received the Covid-19 vaccine and in which arm. This helps to relieve the patient’s anxiety if an enlarged lump is located and reduces the need for further testing, which is common if a swollen lump suggests cancer.
The Society for Breast Imaging has recommended that women do their tests before receiving the vaccine or wait four weeks after the final dose. (Pfizer and Moderna require two doses; Johnson & Johnson, only one.)
Crouse, however, recommends that women maintain their regular schedules instead of postponing the vaccine or mammogram.
“If you can have your mammogram before getting the vaccine, there are no problems,” said Wang, “but if you get the vaccine, you can still have your mammogram and we will take that into account. We didn’t want to discourage people from following their normal displays. “
If a patient has an enlarged lump near a recent vaccine injection site, said Wang, they are advised to monitor it for eight weeks. If it doesn’t go away or still looks abnormal, Wang said, then more tests may be needed.
“If there is any concern that this could be anything other than a reaction to the vaccine,” he said, “we will say, ‘Let’s take another look in eight weeks.'”
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