Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Lobules are a normal part of the breast which produces milk. Lobular carcinoma in situ (LCIS) is the presence and growth of abnormal cells in the lobules of the breast. These abnormal cells do not grow in an uncontrolled manner or spread to other areas of the body like cancer. However, LCIS is considered a risk factor for future breast cancer.


It is not clear exactly what causes LCIS. It is probably a combination of genetics and environment.

Risk Factors

LCIS is more common in premenopausal women, generally between 40-50 years old. Other factors that may increase your chances of LCIS:

  • Family members with breast cancer
  • Increased exposure to estrogen
  • Use of hormone replacement therapy


LCIS does not have symptoms.


LCIS does not appear on imaging tests, nor can it be felt during a manual breast exam. It is generally found by accident during biopsy of other nearby breast tissue.


LCIS does not require treatment.

Frequent follow-up visits and tests to monitor any changes in the breast tissue may be recommended because of the increased risk of breast cancer. If you detect any changes in either breast, call your doctor right away for an appointment.

Other breast cancer prevention treatments may be recommended based on your overall risk of developing breast cancer. If you have a high risk of developing future breast cancer, your doctor may recommend:

  • Medications—To block estrogen receptors on breast tissue cells.
  • Surgery—A double mastectomy with reconstruction may be an option under special circumstances. It is generally considered to be an aggressive option.

Talk to your doctor about the risks and benefits of having these treatments.


There are no current guidelines to prevent LCIS because the cause is unknown.