Benign breast conditions (also known as benign breast disease) are a wide range of non-cancerous breast disorders. Some of these conditions increase the risk of breast cancer and others do not. When it comes to assessing breast cancer risk, these disorders are categorized as either proliferative breast condition (with rapidly multiplying cells) or non-proliferative breast condition.
Proliferative Breast Condition
Proliferative breast conditions are non-cancerous disorders characterized by multiplying (proliferating) cells. Although they are not cancerous themselves, they are linked to an increased risk of breast cancer [47-49]. The most common type of proliferative breast condition is hyperplasia. There are two general types of hyperplasia: usual hyperplasia and atypical hyperplasia.
In usual hyperplasia, the proliferating cells have a normal appearance under a microscope. In atypical hyperplasia, the proliferating cells have an abnormal appearance. Women with confirmed atypical hyperplasia have about four times the breast cancer risk of women without proliferative condition [47,48]. Women with usual hyperplasia have about two times the risk [47].
Non-proliferative Breast Condition
Non-proliferative benign breast conditions—such as cysts—do not appear to be linked to breast cancer. For more information about benign breast conditions, see the Breast Facts section.
Updated 09/12/09
