Fibrocystic Breast Disease
Normal Breast Tissue
The breast is composed of 15-20 lobes of milk-secreting glands that are embedded in fatty tissue. Ducts link the lobes of these glands and have an outlet through the nipple. The area between the lobules and ducts is filled with fatty tissue. Breast tissue itself contains no muscles; however, there are small, very fine ligaments throughout the breast that attach to the skin and determine the shape of the breast. There are no muscles in the breast itself, although pectoral muscles lie just under each breast and over the ribs (AMA 1989).
The breasts undergo changes each month when a female begins to have menstrual periods. Hormones that are implicated in development of breast mammary glands and worsening premenstrual breast symptoms are estrogen and progesterone, the main female hormones, and prolactin, the milk release hormone secreted by the pituitary gland (Lark 1996). An increase in prolactin may also be responsible for some FBC changes because higher levels of prolactin seem to be connected with a higher occurrence of FBC (prolactin levels of over 100 ng/mL may be a causative factor). Often the painful symptoms of FBD will decrease once menstruation begins. In some women, however, the repeated cycles of hormonal stimulation result in chronic inflammation and development of fibrous tissue. When fibrous tissue makes it more difficult for the fluid in breast cysts to escape and be normally absorbed by a woman's body, the cysts become denser, which can cause pain and pressure on surrounding tissues (Lark 1996). This fibrous tissue is similar to the type of tissue in ligaments and scars and feels firm, thick, rubbery, and ridge-like. It may also feel like small or large beads scattered throughout the breast.
In addition to naturally occurring hormones (i.e., estrogen, progesterone, and prolactin), many other natural hormones (hypothalamic, other pituitary hormones, thyroid, parathyroid, adrenal, pineal, pancreas, ovarian, and duodenal hormones) can contribute to FBD (Ayres 1983; AMA 1989). Environmental estrogens, called xenoestrogens, may also contribute to human hormone levels. Xenoestrogens come from phytoestrogens (produced by plants), dietary estrogens from meat and dairy products, and many other chemicals such as pesticides, fertilizers, alklyphenols (used in detergents), and plastics (food packaging) (Nimrod 1996). Additionally, as women approach menopause, they have an additional, complicated decision to make concerning the use of synthetic hormone replacement therapy (HRT) (Lundstrom 2001; Mayo Clinic 2001; Women's Health Initiative Investigators 2002).