Dear concerned911, We have lymphnodes as part of our lymphatic system that run throughout our bodies, and contain lymphocytes which are cells that are part of our bodies immune system. They can become enlarged due to infection, they can also become enlarged because of cancer. The enlargement wouldn't necessarily mean that it is a pre-cursor to cancer.
As to the safety of ultrasounds, radiation is not used during an ultrasound, sound waves are used. The mammogram machines used today need very low amounts of radiation per test. The data to date suggests that the benefit of mammogram procedure far outweighs any risk of radiation exposure.
I am also 32 with BC. Mine was not seen on the mammogram only through the ultrasound. The surgeon that did the biopsy also told me that he did not feel it was cancerous. The pathology report revealed otherwise. The fact is that a lot of lamps are not cancerous and the only way to know for sure is to remove it or do a biopsy. My suggestion is - don't wait and do a biopsy -yes there will be a little scar but you will know for sure about what it is for your peace of mind. Check out breastcancer.org and post your questions there - you'll get a lot of responses from other women who has been through that.
Sana