Lobules are the part of the breast that produces milk. Lobular carcinoma in situ (LCIS) is when there are abnormal cells in the lobules of the breast. These abnormal cells do not grow in an uncontrolled way or spread to other parts of the body like cancer. But, LCIS is a risk factor for 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 who are between 40-50 years old.
LCIS does not have symptoms.
LCIS does not appear on imaging tests. It can’t be felt during a breast exam. It is usually found during a biopsy of other nearby breast tissue.
LCIS does not require treatment.
Your doctor will monitor your breast for changes with:
Take these steps to reduce your overall risk of breast cancer:
American Cancer Society
National Cancer Institute
Canadian Cancer Society
LCIS—lobular carcinoma in situ. Breast Cancer website. Available at:
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Update February 18, 2017. Accessed January 29, 2018.
Lobular carcinoma in situ. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114068/Lobular-carcinoma-in-situ . Updated August 18, 2016. Accessed January 29, 2018.
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. Updated September 20, 2017. Accessed January 29, 2018.
Venkitaraman, R. Lobular neoplasia of the breast. Breast J. 2010;16(5):519-528.
Last reviewed November 2018 by
EBSCO Medical Review Board
Mohei Abouzied, MD, FACP
Last Updated: 5/21/2018