Usually “family history” is limited to parents, siblings, and grandparents, but I know for my nieces they count my breast cancer as family history too. So I think that your question is “In genetics, what is family history”? For that, I believe the women on your mom’s side would be important part of your family history. But I’m not a geneticist, so…
Your case sounds very similar to how my cancer was found. My sister was diagnosed at 28 so I’d been getting screened every 6 months since I was 26. I moved and went to a new facility and had my mammogram where they saw a mass so they did an US. On US, they didn’t see that mass but did see another mass. The radiologist said that it didn’t look like cancer because it didn’t have the spider-like appearance and he didn’t see any calcifications. He measured it at 1.1 cm. He recommended we check it again at my next visit.
I told him no way. I wanted it biopsied — now. My sister had also been told not to worry that it was probably nothing (thankfully, she spoke up for herself and is NED). I had the biopsy and the radiologist assured me that all of the samples he took out looked very normal. Four days later I got a call at work that I had cancer. I wasn’t surprised — I already knew that it would be. And I honestly felt like now I could quit living in fear of getting breast cancer and could deal with it and move on. I was lucky to be working at UCSF (I had my biopsy at a private practice clinic) and had an “in” with the surgeons and oncologists, so I transferred my records and got appointments set up quickly. When they did pathology on what remained of the tumor, it had grown to 1.9 cm in a really short time.
Advocate for yourself. I agree that you need either to have a different radiologist’s review of the mammogram and US or ask your PCP to go to bat for you to get the biopsy without new scans. Obviously it’s up to you — if you’re ok waiting 6 months, don’t be scared by my or other people’s stories (I’m 13 years NED, btw).