Tumor with tentacles - scheduling biopsy tomorrow EEK

Hi all! Trying to stay calm, but obviously anxious. I've been having nipple discharge just from my left breast for about a year, and then recently have had pains on the side and into my armpit and collarbone. Thought I felt a lump in that area, as well, so my gyno referred me to have an ultrasound and mammogram.

Sure enough, they found a mass right where it's been hurting, about 1cm, on the outside of my left breast. I saw the image, and it looks like a small bean with tentacles coming off of it, and she said it's pulling the surrounding tissue toward it, causing the symptoms. She scheduled me for a biopsy and said best-case scenario it's a high-risk benign tumor. Worst case it's bc. I did some research and apparently a mass with tentacles isn't a good sign, especially because it seems to be pulling in other tissue, but I haven't gotten the written radiology report, so I don't know exactly what it says.

I just turned 30 but have an insane history of female cancers (including bc on my mom's side), so definitely freaking out a bit but trying to stay positive. Even just reading others' stories has been so comforting, and hopefully it all turns out to be nothing! Anyone else have these symptoms and/or have experience with masses that resemble this? 1cm isn't bad right? Also, is it common that she knew I'd need surgery regardless? If it turned out to be benign wouldn't they just leave it in?

Thanks in advance for all of your advice, it's much needed at the moment