We often don’t think of the armpit as a particularly attractive or important part of the body - it sort of exists by default. But, in its more interesting terminology, the axilla, we can talk about it as more than just a tucked away fold.
The axilla is made up of fat and blood vessels and may contain breast tissue. This means that when we image the breasts with a mammogram, we must look at the axilla as well. This is done so that any breast tissue present is included and because the lymph nodes related to the breast are primarily located in the axillary tissue. Breast cancer if it spreads to the lymph nodes will often head to the group of nodes in the axilla on that side, so it is an important part of your complete picture.
The lymph nodes of the axilla can be abnormal and symptomatic (presenting as an axillary mass or focal tenderness) with lots of conditions other than breast cancer. Some findings will be benign, such as infections - often related to infections in the tissues in the arm or the breast. Other times, enlarged lymph nodes can be an indicator of underlying diseases, like sarcoidosis and lymphoma. Sometimes, the enlarged lymph nodes we see in the armpit are the first sign of a widespread unknown illness - like lymphoma which was diagnosed in these enlarged axillary lymph nodes in this patient’s mammogram.
We can evaluate the axilla on mammography, but if there are symptoms we may add ultrasound or MRI. On mammography, the axilla is included on the oblique views - remember the part where it feels like your whole breast is being pulled onto the machine? - we’re trying to get the axillary tissue on the image. Biopsy may ultimately be needed, based on the results of the imaging evaluation.
So, we hope we have shed some light on first, why your mammography technologist works hard to position you so we can see that axilla and second, on what sorts of things can be found in that axilla. It’s an important part of total breast evaluation - not just a body part to ignore!
Originally published 11/19/13 on mammographykc.com.