Lobular carcinoma in situ (LCIS)

Lobular carcinoma in situ (LCIS) occurs when abnormal cells form in the lobules of the breast, which are the glands that produce milk. “In situ” means “in the original place,” and in LCIS the abnormal cells do not spread beyond the lobule into nearby breast tissue. This condition is not breast cancer, but may signal an increased risk of developing it.