By the time they’ve reached their mid-forties or so, almost half of all women develop some degree of a condition called fibrocystic breast syndrome (FBS) in which their breast tissue becomes either more dense (“fibrous”) or it contains fluid-filled cysts, which can be tender or “lumpy.” In addition, because these cysts are under hormonal control, they often change size during a woman’s cycle and become exquisitely tender and painful during the week or so before her menstrual flow begins.