Lobular Carcinoma in Situ (LCIS)

Lobular carcinoma in situ (LCIS) is a type of breast change that is sometimes seen when a breast biopsy is done. In LCIS, cells that look like cancer cells are growing in the lining of the milk-producing glands of the breast (called the lobules), but they don’t invade through the wall of the lobules.

LCIS is not considered to be cancer, and it typically does not spread beyond the lobule (become invasive breast cancer) if it isn’t treated. But having LCIS does increase your risk of developing an invasive breast cancer in either breast later on, so close follow-up is important.

LCIS and another type of breast change (atypical lobular hyperplasia, or ALH) are types of lobular neoplasia. These are benign (non-cancerous) conditions, but they both increase your risk of breast cancer.


LCIS is diagnosed by a biopsy, in which small pieces of breast tissue are removed and checked in the lab. Often, LCIS does not cause a lump that can be felt or changes that can be seen on a mammogram. In most cases, LCIS is found when a biopsy is done for another breast problem that’s nearby.

You can learn more about pathology reports showing 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, women with LCIS should make sure they have regular breast cancer screening tests and follow-up visits with a health care provider for the rest of their lives.


Having LCIS does increase your risk of developing invasive breast cancer later on. But since LCIS is not a true cancer or pre-cancer, often no treatment is needed after the biopsy.

Sometimes if LCIS is found using a needle biopsy, the doctor might recommend that it be removed completely (with an excisional biopsy or some other type of breast-conserving surgery) to help make sure that LCIS was the only abnormality there. This is especially true if the LCIS is described as pleomorphic (meaning the cells look more abnormal) or if it has necrosis (areas of dead cells), in which case it might be more likely to grow quickly.

Even after an excisional biopsy, if pleomorphic LCIS is found, some doctors might recommend another surgery to make sure it has all been removed. This is because this type of LCIS may be more likely to turn into invasive cancer.

Reducing breast cancer risk or finding it early

Women with LCIS are at higher risk for breast cancer, so close follow-up is very important. Close follow-up of both breasts is important because women with LCIS have the same increased risk of developing cancer in both breasts. Women should also talk to a health care provider about what they can do to help reduce their breast cancer risk. Options for women at high risk of breast cancer because of LCIS may include:

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: September 10, 2019 Last Revised: September 10, 2019



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