This patient support community is for discussions relating to breast cancer, biopsy, genetics, chemotherapy, hormone therapy, lumps, lumpectomy, lymph node dissection, lymphedema, mammograms, mastectomy, radiation therapy, reconstruction, and self exams.
With the present ultrasound and mammographic developments, I believe that you doctors are taking the right course in assessing the lesion. Breast lumps or nodules that enlarges would warrant a biopsy or further investigation, to rule out a neoplastic process. The increased in vascularity is also a factor in considering a biopsy since fibroadenomas are usually non-vascular.
However, it is still too early to tell if this is indeed benign or something else. The mammogram can also give us a clue if the lesion is probably benign or malignant, and it will be helpful to ask your radiologist about the BIRADS category of the mammogram (you can learn more about BIRADS here: http://biradsclass.blogspot.com/). One point that I want to make is that vascular lesions have a bigger tendency to bleed when biopsied and I recommend discussing the procedure very well with your surgeon.
Regards and God bless.