Breast cysts are accumulations of fluid in the breast. Cysts can usually be felt in the form of smooth, rounded lumps. They can be moved around in the breast and may also be found deep in the breast tissue. Cysts are most common in pre-menopausal women, but can occur in women after menopause, especially if they are on hormone replacement therapy (HRT).
Normally, only one or two cysts will show up at a time, but in some cases, multiple cysts may appear. Cysts are usually confirmed with mammography or ultrasound. Ultrasound is a very effective diagnostic tool in defining whether the breast abnormality is indeed a cyst or a solid mass.