Micrograph showing apocrine metaplasia associated with FCC. FNA specimen. Pap stain. The exact mechanism of the condition is not fully understood, though it is known to be tied to hormone levels, as the condition usually subsides after menopause and is also related to the menstrual cycle. Post-menopausal women placed on hormone replacement therapy have also reported symptoms of<unk> indicating hormones may play a role.<unk>  is a cumulative process, caused partly by the normal hormonal variation during a woman's monthly cycle. The most important of these hormones are estrogen, progesterone and prolactin. These hormones directly affect the breast tissues by causing cells to grow and multiply. Many other hormones such as TSH, insulin, growth hormone and growth factors such as TGF-beta exert direct and indirect effects amplifying or regulating cell growth. Years of such fluctuations eventually produce small cysts and/or areas of dense or fibrotic tissue. Multiple small cysts and an increasing level of breast pain commonly develop when a woman hits her 30s. Larger cysts usually do not occur until after the age of 35. Over time, presumably driven by aberrant growth signals, such lesions may accumulate epigenetic, genetic and karyotypic<unk>  such as modified expression of hormone receptors and loss of heterozygosity. Several variants of<unk>  may be distinguished and these may have different causes and genetic predispositions. Adenosis involves abnormal count and density of lobular units, while other lesions appear to stem mainly from ductal epithelial origins. There is preliminary evidence that iodine deficiency contributes to<unk>  by enhancing the sensitivity of breast tissue to estrogen.
Fibrocystic breast changes
Breast cancer
Papillomatosis of breasts
Multiple cutaneous leiomyoma
Tuberous breasts
Breast mass
Trichoadenoma
Duct ectasia of breast