The breast contains lobes where milk is made. Lobular carcinoma in situ is a condition where there are cell changes in the lining of these lobes.
Lobular carcinoma in situ (LCIS, also called lobular neoplasia) is not a cancer. It is a condition where there are changes in the cells lining the lobes (see diagram below) where milk is made in the breast.
These changes indicate that a woman has a higher risk of developing breast cancer later in life. But even so, most women with LCIS never develop breast cancer. A woman’s risk of developing cancer is similar in both breasts, no matter which breast LCIS is found in. Some women have LCIS in both breasts.
LCIS is more common in women who have not yet reached the menopause.