An Overview of Lobular Carcinoma in Situ (LCIS)

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Lobular carcinoma in situ (LCIS), often called lobular neoplasia in situ, is a rare, benign (noncancerous) condition. It is characterized by hyperplasia (excess cell proliferation) confined within the lobules of a woman's breasts. LCIS is not breast cancer. However, women who are diagnosed with the condition have an increased risk of developing breast cancer later in life.

LCIS is typically diagnosed in young women who have not gone through menopause. There are several treatment options available to them, and the main objective of treatment is the prevention of breast cancer.


It is rare to have any symptoms with LCIS. It doesn't typically cause breast lumps, pain, discomfort, or a change in the appearance of the breasts.

This condition is typically detected by diagnostic testing, such as a mammogram or a breast biopsy, done for another reason.

It is not uncommon for multiple lobules (areas of the breasts that produce milk that flows through the ducts and out through the nipples during lactation) to be involved.

In about a third of diagnosed cases, areas of LCIS are found in both breasts.


LCIS is hyperplasia (overgrowth) of cells in the lobules. It may be associated with a genetic tendency, as there is an increased rate of LCIS among women who have family members with breast cancer.

Besides a family history of breast cancer, there are no known risk factors or causes that increase the chances of developing LCIS. The overgrowth of cells is believed to be related to a mutation (alteration of the genes) in some breast cells, which causes them to become abnormal. These cells do not spread to nearby tissue or metastasize further.

The tendency for this condition to develop in premenopausal years could be related to estrogen. A large research study showed that most of these tumors are estrogen receptor positive (ER+), which suggests that the effects of estrogen during the premenopausal years could influence growth if LCIS.

Doctor talking with patient in office
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Sometimes LCIS can be visualized on a mammogram, although it might not always be apparent on routine imaging. If you have a suspicious lesion on a screening mammogram, your healthcare provider might recommend a breast magnetic resonance imaging (MRI) test or an ultrasound.

LCIS may be identified on a biopsy, and it can be detected if you have a breast biopsy for another reason, such as breast cancer in a different part of the breast.

On a biopsy, the cells of LCIS typically do not look very different from normal cells found in the breast lobules, but the microscopic appearance is characterized by overgrowth.

Differential Diagnoses

A few other conditions—described as lobular breast cancers—also involve the lobules of the breasts, but they are distinct from LCIS despite the similar sounding names. Atypical lobular hyperplasia of the breast and invasive lobular breast cancer are both characterized by abnormal cells on a biopsy that appear different from cells seen in LCIS; they are also more aggressive.

Invasive lobular breast cancer is associated with a worse prognosis and requires more aggressive treatment than other conditions that involve the breast lobules.

Breast Cancer Risk After LCIS Diagnosis

It is estimated that women with LCIS have 7 to 12 times the risk of developing breast cancer compared to women without LCIS. Most breast cancers involve the milk ducts and not the lobules, and this tendency does not change if you have had LCIS.

LCIS is a sign of an increased predisposition to breast cancer, but not necessarily lobular breast cancer. LCIS is not considered a precursor of breast cancer, and the cells do not change or become cancer cells.


Given that LCIS is not considered to be true cancer or even a pre-cancer, your healthcare provider may not recommend that you begin active treatment.

However, since LCIS indicates that you are at a higher risk of developing invasive cancer in the future, you need to have close follow-up of your breast health.


You will be encouraged to do regular breast self-exams, make follow-up office visits, get a mammogram every six or 12 months, and, if indicated, have other screening tests (such as genetic testing for breast cancer).

Both breasts must be followed, as women who have LCIS in one breast have just the same risk of developing cancer as women who have the condition in both breasts. Also, LCIS in one breast increases the risk of developing​ cancer in either breast.


If you are diagnosed with LCIS and have a history of breast cancer in your family or carry breast cancer genes, this puts you at an even higher risk of developing breast cancer. Your healthcare provider may suggest that you consider taking hormone therapy to lower your risk of developing breast cancer.

Drugs such as Arimidex (anastrozole), Aromasin (exemestane), Evista (raloxifene), or Nolvadex (tamoxifen) may be recommended. With the exception of tamoxifen, the other drugs are suitable for use only by postmenopausal women. 


Some women, particularly those with a strong family history of breast cancer, may opt to undergo a bilateral simple mastectomy, which is the removal of both breasts. Since LCIS carries an increased risk of breast cancer in both breasts, both are removed to lower the risk.

Simple mastectomy does not involve removing the axillary (under the armpits) lymph nodes. They are typically removed when metastatic (spreading) breast cancer has invaded them. Women choosing to have a simple mastectomy have the option of reconstruction.

Preventative breast cancer surgery is a very personal decision and is a choice that few women select. That, however, certainly does not mean it may not be the right decision for you.

A Word From Verywell

LCIS is a rare condition. If you have it, there is a chance that it might not be detected at all. However, if it is detected, there is no need to panic. While it is associated with a higher risk of breast cancer, most women who are diagnosed with LCIS do not develop breast cancer. And even if you are diagnosed with the disease at some point in the future, it is important for you to know that breast cancers that are detected early can be treated, typically resulting in a cure and very good survival.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Symptoms and Diagnosis of LCIS.

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  4. Mao K, Yang Y, Wu W, Liang S, Deng H, Liu J. Risk of second breast cancers after lobular carcinoma in situ according to hormone receptor statusPlos One. 2017;12(5). doi:10.1371/journal.pone.0176417.

  5. Clauser P, Marino MA, Baltzer PA, Bazzocchi M, Zuiani C. Management of atypical lobular hyperplasia, atypical ductal hyperplasia, and lobular carcinoma in situExpert Review of Anticancer Therapy. 2016;16(3):335-346. doi:10.1586/14737140.2016.1143362.

  6. Johns Hopkins Medicine. Invasive Lobular Carcinoma (ILC).

  7. Marmor S, Jerome-d'emilia B, Begun JW, et al. Trends in lobular carcinoma in situ management: endocrine therapy use in California and New Jersey. Cancer Causes Control. 2019;30(2):129-136. doi:10.1007/s10552-019-1126-4

By Jean Campbell, MS
Jean Campbell, MS, is a breast cancer survivor and advocate, and the founding director of the American Cancer Society Patient Navigator Program.