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Lobular Carcinoma in Situ (LCIS)
Lobular carcinoma in situ (LCIS) is a type of breast change that is often found when a breast biopsy is done for some other reason, such as to check an area of fibrocystic change. LCIS does not usually cause symptoms such as a breast lump or show up on mammograms on its own.
Is LCIS breast cancer or a precancer?
LCIS is not cancer. And it is usually not considered to be a precancer. In LCIS, cells that look like cancer cells grow in the lining of the milk-producing glands (lobules) of the breast, but they don’t invade through the wall of the lobules. And if LCIS isn’t treated, it typically does not become invasive breast cancer.
While LCIS is not cancer, having LCIS does increase your risk of developing an invasive breast cancer in either breast in the future. See "How does LCIS affect breast cancer risk?"
LCIS and another type of breast change called atypical lobular hyperplasia, or ALH, are types of lobular neoplasia. These are conditions in which cells in the breast lobules grow and multiply more than usual. While they are not cancer, having either of them increases your risk of breast cancer.
Types of LCIS
There are 3 different types of LCIS.
- Classic LCIS: The cells lining the lobules of the breast are smaller and are about the same size.
- Pleomorphic LCIS: The cells lining the lobules of the breast are larger and look more abnormal.
- Florid LCIS: The cells lining the lobules have grown into a group and formed a mass. This typically has an area of dead cells in the middle called central necrosis.
Diagnosing LCIS
Classic LCIS usually doesn't cause a lump that can be felt or changes that can be seen on a mammogram. But pleomorphic and florid LCIS are sometimes found this way. Most often, LCIS is found when a small amount of breast tissue is taken to analyze for another problem that’s nearby. This is called a breast biopsy.
You can learn more about biopsy results in pathology reports that show LCIS in Understanding Your Pathology Report: Lobular Carcinoma In Situ.
How does LCIS affect breast cancer risk?
Women with LCIS have about a 7 to 12 times higher risk of developing invasive cancer in either breast. For this reason, doctors typically recommend that women with LCIS have regular breast cancer screening tests and follow-up visits with a health care provider for the rest of their lives.
Does LCIS need to be treated?
Since LCIS is not a true cancer or precancer, often no treatment is needed after the biopsy. But there are times when a health care team may recommend treatment.
When LCIS is found on a needle biopsy
Sometimes if LCIS is found using a needle biopsy, the doctor might recommend that it be removed completely. This helps make sure that there wasn’t anything else abnormal there aside from the LCIS. It is typically removed with an excisional biopsy or some other type of breast-conserving surgery. Removal is especially important if the LCIS is described as pleomorphic or florid, in which case it might be more likely to grow quickly.
When LCIS is found on an excisional (surgical) biopsy
Usually no further treatment is needed if LCIS is found and removed with an excisional biopsy. But if pleomorphic or florid LCIS is found, some doctors might recommend another surgery to make sure all of it has been removed.
Reducing breast cancer risk or finding it early
Close follow-up is important after a diagnosis of LCIS because of the increased risk of breast cancer. This increased risk is in both breasts. It’s also important to talk to your health care provider about what you can do to help lower your breast cancer risk. Options for women at high risk of breast cancer because of LCIS may include:
- Getting breast exams more often, likely every 6 or 12 months along with the yearly mammogram. Additional imaging with a breast MRI or other tests may also be recommended, especially if a woman has other factors that raise her risk of breast cancer.
- Making lifestyle changes to lower breast cancer risk. To learn more, see Can I Lower My Risk of Breast Cancer?
- Taking medicine to help lower the risk of breast cancer. For more on this, see Deciding Whether to Use Medicine to Reduce Breast Cancer Risk.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Hartmann LC, Sellers TA, Frost MH, et al. Benign breast disease and the risk of breast cancer. N Engl J Med. 2005;353:229-237.
King TA, Reis-Filho JS. Chapter 22: Lobular carcinoma in situ: Biology and management. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2014.
National Comprehensive Cancer Network. Clinical Practice Guidelines in Oncology: Breast Cancer
Screening and Diagnosis. Version 1.2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast-screening.pdf on October 28, 2021.
National Comprehensive Cancer Network. Clinical Practice Guidelines in Oncology: Breast Cancer Risk Reduction. Version 1.2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast_risk.pdf on October 28, 2021.
Renshaw AA, Gould EW. Long term clinical follow-up of atypical ductal hyperplasia and lobular carcinoma in situ in breast core needle biopsies. Pathology. 2016;48:25-29.
Sabel MS, Collins LC. Atypia and lobular carcinoma in situ: High-risk lesions of the breast. UpToDate. 2021. Accessed at https://www.uptodate.com/contents/atypia-and-lobular-carcinoma-in-situ-high-risk-lesions-of-the-breast on October 28, 2021.
Last Revised: May 26, 2026
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