Hi,
Sorry,I don't know what happened with my previous post.
Anyway, I wanted to tell you that the nodule found in your breast is a solid nodule and in this case a Biopsy is usually recommended.A BIRADS category 4,means that the nodule is suspicious because of the indistinct margins, but until a biopsy is done,no one can tell you for sure what the nature of this lump could be.
Many BIRADS 4 return a benign finding though....So keep a positive attitude and lets hope that all will be fine.
Best wishes and good luck...