Overview of Lobular Carcinoma in Situ (LCIS)

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Lobular carcinoma in situ (LCIS), also often called lobular neoplasia in situ, is a rare benign (non-cancerous) condition. It is characterized by hyperplasia (excess cell proliferation) confined within the lobules of a woman's breasts.

LCIS is typically diagnosed in young women who have not gone through menopause. LCIS is not breast cancer, but women who are diagnosed with the condition have an increased risk of developing breast cancer.

There are several treatment options and the main objective of treatment is focused on the prevention of breast cancer.

Symptoms and Causes

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.

It is not uncommon for multiple lobules to be involved. In about a third of diagnosed cases, areas of LCIS are found in both breasts.


The lobules are the areas of the breasts that produce milk during lactation (breastfeeding). Breast milk flows from the lobules through the ducts, and then out of the breasts through the nipples.

LCIS is hyperplasia (overgrowth) of cells in the lobules. It may be caused by a genetic tendency, and there are known not risk factors or causes that increase the chances of developing LCIS.


Sometimes LCIS can be visualized on a mammogram, although it might not always be apparent on a routine mammogram. If you have a suspicious lesion on a screening mammogram, your doctor 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.

Lobular Breast Cancer

A few other conditions also involve the lobules of the breasts— atypical lobular hyperplasia of the breast and invasive lobular breast cancer. These conditions are more aggressive than LCIS. They are both characterized by abnormal cells on a biopsy and are distinct from LCIS.

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

Risk After LCIS Diagnosis

It is estimated that 20 to 40 percent of women with LCIS may be diagnosed with separate invasive breast cancer over the next 15 years—a rate that is between three and five times the usual risk of developing breast cancer.

Most breast cancers involve the milk ducts and not in 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 physician 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.

Follow Up

You will be encouraged to do regular breast self-exams, make follow-up office visits, get a mammogram every 6 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 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 physician 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. The lymph nodes 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.

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 breast cancer 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 cure and very good survival.

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