Cysts are fluid filled pockets that form in the tissues of the breast, causing a mass.
Mammography or ultrasound can suggest that a breast mass is a cyst. A cyst is diagnosed definitively when a needle is inserted into it and the doctor is able to draw out fluid. This is ideal for women with cysts, because the procedure both diagnoses and removes the cyst at the same time. A cyst should completely disappear when drained and the tension of it is relieved. If the fluid removed is not bloody, it does not have to be sent to a lab for analysis, unless the women is post-menopausal and not on hormone replacement.