Lobular carcinoma in situ (LCIS) is when there are abnormal cells in the lobules of the breast. The lobules are the part of the breast that produces milk. LCIS is not cancer. However, it can raise the risk of future breast cancer.
It is not clear what causes LCIS. It is likely due to a change in a gene.
LCIS is more common in premenopausal women between 40 to 50 years old.
LCIS does not have symptoms.
LCIS does not appear on imaging tests. It cannot be felt during a breast exam. It is usually found during a biopsy of other nearby breast tissue.
LCIS does not require treatment.
The doctor will monitor the breast for changes with:
The risk of breast cancer may be reduced by:
American Cancer Society
National Cancer Institute
Canadian Cancer Society
LCIS—lobular carcinoma in situ. Breast Cancer website. Available at:
...(Click grey area to select URL)
Accessed March 19, 2021.
Lobular carcinoma in situ. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/lobular-carcinoma-in-situ. Accessed March 19, 2021.
Lobular carcinoma in situ (LCIS). American Cancer Society website. Available at: https://www.cancer.org/cancer/breast-cancer/non-cancerous-breast-conditions/lobular-carcinoma-in-situ.html. Accessed March 19, 2021.
Wen HY, Brogi E. Lobular carcinoma in situ. Surg Pathol Clin. 2018;11(1):123-145.
Last reviewed January 2021 by
EBSCO Medical Review Board
Mohei Abouzied, MD, FACP
Last Updated: 3/19/2021