I came to read your second post before answering, so I will answer you here. I hope you get good news on Thursday that it is indeed a cyst. No matter what they think it is, they need to take some action to be sure. If it is a cyst, then they can do a needle aspiration and I believe they test the fluid to make sure there are no cancer cells. They usually are not, I believe. If they determine it is a lump you can still have a needle biopsy done, a core biopsy, or a lumpectomy biopsy. I am of the old school and I would prefer a full biopsy. My daughter's mammo showed it was most likely cancer, so a needle biopsy was done to acertain that it was before she made arrangements to have mastectomy and reconstructive surgery. The surgeon had told her a mastectomy was necessary if it was cancer due to the size and location, she was fearful it was into the chest wall, which it was not. Six years later she is doing fine.
Let us know, we will be happy to share your good news and be here to help if you need further testing, etc. Hugs MK