Lobular Carcinoma (Invasive and in Situ)

Most breast cancers start in the ducts of the breasts, but some begin in the glands that produce milk, called the lobules.

These are:

  • Invasive lobular carcinoma (ILB), also called infiltrating lobular carcinoma
  • Lobular carcinoma in situ (LCIS), also called lobular neoplasia

The symptoms, diagnosis, and treatment for each are different.

What Is Invasive Lobular Carcinoma?

ILC is the second most common form of invasive breast cancer. It begins in one of the breast lobules, then spreads to other parts of the breast. It’s more likely to be found in both breasts than other types of breast cancer. It can also spread to other areas in the body.

Symptoms of Invasive Lobular Carcinoma

There may not be any symptoms at first. But you might notice:

  • Thickening or hardening in the breast (as opposed to a distinct lump)
  • An area of swelling or fullness
  • A change to the texture of skin on your breast or nipple, like dimples or an irritated, red or scaly area
  • Your nipple turns inward
  • Pain in your breast or nipple
  • Nipple discharge that isn’t milk
  •  A lump under your arm

Invasive Lobular Carcinoma Diagnosis

Often, ILC can’t be found by a mammogram. If you have a suspicious area, your doctor should order a biopsy to analyze cells. Most biopsies use a needle to extract a sample of cells from the breast. In some instances, though, the doctor will remove a larger sample -- or the entire tumor -- for analysis.

The biopsy will help the doctor decide whether you have invasive lobular carcinoma and how aggressive it may be.

Invasive lobular carcinoma spreads. So your doctor may recommend additional tests to search for cancer in other parts of your body. These tests may include:

  • CT scan . It's a powerful X-ray that makes detailed pictures inside your body.
  • PET scan . Used together with a CT scan, this test can help find cancer in lymph nodes and other areas.
  • MRI . It uses strong magnets and radio waves to make pictures of the breast and other structures inside your body.
  • Bone scan. A radioactive substance called a tracer is injected into your arm, and pictures are taken to find out if cancer may have traveled to your bones.
  • Chest X-ray: It uses radiation in low doses to make images of structures inside your chest.

Your doctor will also take samples from your lymph nodes in the armpits to check for cancer. She might remove the lymph nodes in your armpits. This is called axillary lymph node dissection.

The results of your exams will determine the stage of your breast cancer and the best treatment options.


Invasive Lobular Carcinoma Treatment

Most women with invasive lobular carcinoma have surgery to remove the cancer from the breast. In most cases, the cancer can be taken out without removing the entire breast. It will depend on the size of your tumor and how much it has spread throughout your breast and surrounding lymph nodes.

Your doctor may also recommend treating it with chemotherapy, radiation therapy, hormone therapy, or some combination of the three. Chemotherapy and hormone therapy are systemic treatments. They target cancer cells throughout your entire body. Radiation specifically focuses on the area around your breast cancer. Cells in invasive lobular carcinoma often contain estrogen and progesterone receptors. Hormone treatments specifically target these cells.

Other targeted therapy may be helpful if the cancer is HER2-positive.

Prognosis for Invasive Lobular Carcinoma

It’s hard to say exactly what the odds are because cancer affects everyone differently. Plus, how well you do depends on how early you catch the cancer and how well you responded to treatment.

In general, about 90% of all women with breast cancer are still alive 5 years after diagnosis. While there isn’t much data for specific types of breast cancer, 5-year survival rates are tracked by stage at diagnosis -- or how far the cancer has spread:

  • Regional (cancer has spread to lymph nodes near the breast): 85.3%
  • Distant (cancer has metastasized): 27%

What Is Lobular Carcinoma in Situ?

LCIS isn’t cancer, but it’s thought to be a sign that breast cancer may develop. With this condition, there are abnormal cells in multiple lobules of the breasts, but these cells rarely spread to other parts of the breast or body. The phrase "in situ" means "in its original place."

Areas of lobular carcinoma in situ are sometimes seen in both breasts.

Even though this condition doesn’t spread, it’s important to keep an eye on it. Between 20% to 40% of women with this condition will develop a separate invasive breast cancer -- one that will grow outside its original location -- within the next 15 years. Most of the time, these later cancers begin in the milk ducts rather than the lobules.


Lobular Carcinoma in Situ Diagnosis

You often won’t have any symptoms with LCIS. Many times, it’s not even found by routine mammograms. Unlike other breast cancers and related conditions, LCIS doesn’t cause lumps. It’s most commonly diagnosed when a biopsy is done for another condition.

The biopsy findings for LCIS can be very similar to an actual breast cancer called ductal carcinoma in situ. Because of this, you may want to ask for a second opinion to confirm your diagnosis.

Lobular Carcinoma in Situ Treatment

Some women with LCIS won’t need immediate treatment with surgery or medicines. Instead, the doctor may recommend keeping a close eye on your condition. That means regular breast self-exams, office visits, and routine mammograms or other tests such as MRIs.

If you have a family history of breast cancer and are at an increased risk, your doctor may suggest you take medications such as anastrozole (Arimidex), exemestane (Aromasin), raloxifene (Evista), tamoxifen (Nolvadex). These drugs may lower the chance that you’ll develop invasive breast cancer.

Some women need surgery to remove tissue in the area of the LCIS.

If you’re at a higher risk, you might choose preventive surgery called a prophylactic mastectomy. The procedure removes one or both breasts. Doing so can significantly reduce the risk of breast cancer in the future.

WebMD Medical Reference Reviewed by Laura J. Martin, MD on March 17, 2019



Breastcancer.org: “Lobular carcinoma in situ,” “Invasive lobular carcinoma,” ”Bone Scans,” “LCIS and Breast Cancer Risk,” ”Treatments for LCIS,” “Test for Diagnosing ILC,” and “Systemic Treatments for ILC: Chemotherapy, Hormonal Therapy, Targeted Therapies,” “Signs and Symptoms of ILC.”

Breast Cancer Network of Strength: “Lobular carcinoma in situ” and “Infiltrating lobular carcinoma.”

National Cancer Institute: “Lobular carcinoma in situ,” “Cancer Stat Facts: Female Breast Cancer.”

American Cancer Society: “What is breast cancer?” and "Special Section: Breast Carcinoma in Situ."

College of American Pathologists: “Lobular carcinoma in situ“ and "Invasive lobular carcinoma.”

MedlinePlus: “Tamoxifen.”

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