Can a swollen lymph node show up on a mammogram or regular x-ray if it is close to the breast area?

Possibly: There are lymph nodes in the axillary area (armpit) as well as within the breast tissue called intramammary node. Enlarged as well as normal nodes can be frequently seen on a mammogram. If you have a newly swollen or enlarged node or if your mammogram showed a new change, further evaluation is needed. An infectious or a malignant process need to be ruled out.

A lymph node : can show up on a mammogram if it is in the breast or in the adjacent axillary tail. On standard X-ray, due to the inherent relatively low soft tissue contrast resolution, lymph nodes will generally not be discernible unless very large.