Lobular Carcinoma in Situ (LCIS)

Lobular carcinoma in situ (LCIS), also known as lobular neoplasia, is a rare condition in which abnormal cells develop in the milk glands, known as lobules, in the breast. These abnormal cells are not considered to be breast cancer and don’t require any treatment beyond surgical removal. However, the presence of LCIS may increase the patient’s risk of developing breast cancer in either breast in the future. More aggressive breast cancer screening or preventative measures may be recommended.


LCIS doesn’t cause any symptoms in most patients. In rare cases, the patient may notice a lump in their breast.

Causes and Risk Factors

The cause of LCIS is unknown. Risk factors associated with LCIS include:

  • Being over 40 years of age
  • A family history of breast cancer
  • Using combination estrogen-progestin hormone replacement therapy for more than three to five years after menopause


LCIS is typically not noticeable on a mammogram. Often, the condition is discovered when a biopsy is performed on another area of concern. During a biopsy, a sample of the abnormal tissue will be removed using a needle. The doctor may use stereotactic images, such as mammography or ultrasound, to guide the needle to the area of concern. A specialist, known as a pathologist, will examine the tissue sample and determine if cancer is present.


Treatment of LCIS will be personalized for each patient and may include observation, preventative medicine or surgery.

  • Observation. Patients with LCIS have an increased risk of developing other types of breast cancer, requiring more careful observation of their breast health. This may include two clinical breast exams performed by a member of the medical team, more frequent self-exams, yearly mammograms or other imaging tools, such as magnetic resonance imaging (MRI), to observe any changes in the breast tissue.
  • Preventative Medicine. For some patients, preventative chemotherapy medicine, known as chemoprevention, may be used to lower their risk of developing breast cancer. The most common chemoprevention medications are tamoxifen and raloxifene, which can reduce the risk of breast cancer by half. These medications may not be appropriate for patients with multiple heart disease risks or other health concerns.
  • Surgery. In some cases, an excisional biopsy, which removes the affected tissue while preserving as much of the natural breast tissue as possible, may be performed. In rare cases, a preventative mastectomy, a procedure that removes all of the breast tissue, may be the best course of treatment. There are different forms of mastectomy surgeries including nipple-sparing and skin-sparing options.