What is the possibility of breast cancer in BRCA1 positive?

Hi doctor,

I am 30 years old. I have BRCA1 genetic mutation that is still undergoing more research as they are not sure of the exact risk yet. My mom had breast cancer at the age of 56 and her cousin had the same at the age of 46. They were both positive to hormonal therapy. Another cousin had ovarian cancer at the age of 49. They are all cancer-free now.

I have a fibrocystic breast and one fibroadenoma confirmed with a biopsy three years ago. I had an ultrasound scan three months ago and found more cysts and nothing major to worry about. I had another ultrasound a week ago as I felt a new little lump. That lump turned out to be another cyst, but the doctor found another lump she had not seen three months before. It has regular borders and it is moveable but it has some vascularities. She says it cannot be a cyst and could be a fibroadenoma but it has to be confirmed by a biopsy which I will have next week.

I know that sometimes triple-negative breast cancer lumps can be mistaken for fibroadenoma but how likely is that chance? I am feeling quite anxious and worried. With a fibrocystic breast is it possible to have a fibroadenoma appear this fast? Or is it possible that an ultrasound would have missed it last time?

Thank you doctor,

I am considering that now. With the characteristics of the lump I have sent you, could it be benign or does it seem malignant?