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Your Breast Pathology Report: Lobular Carcinoma In Situ (LCIS)

Learn about some of the medical terms in a pathology report that shows lobular carcinoma in situ (LCIS).

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Types of breast biopsies

A biopsy is a procedure that removes small pieces of tissue so they can be examined under a microscope or tested. A breast biopsy can be done by: 

  • Needle biopsy, where a hollow needle is used to remove samples from an abnormal area in your breast.
  • Incisional biopsy, a type of surgical biopsy in which only part of an abnormal area is removed.
  • Excisional biopsy, a type of surgical biopsy that removes the entire abnormal area, often with some of the surrounding normal tissue. It is much like a lumpectomy, a type of?breast-conserving surgery.

After biopsy samples are collected from your breast, they are studied by a pathologist, a doctor who specializes in diagnosing and classifying disease. After testing the samples, the pathologist creates a pathology report on what was found. Your doctors can use this report to help manage your care.

What is in-situ carcinoma of the breast?

The normal breast contains milk ducts (tiny tubes) that end in groups of sacs called lobules (where milk is made). Ducts, lobules, and many other organs in the body are lined by a layer of tissue called epithelium.

color illustration showing the structure of the breast (including location of areola, nipple, collecting ducts, ducts, lobules, fatty connective tissue, duct cells and lobular cells)

In-situ carcinoma, also known as carcinoma in situ or CIS, means that abnormal cells are growing in the lining layer (epithelium) but they aren’t invading into deeper tissue layers.

On the other hand, if the carcinoma cells have grown (invaded) deeper than the lining layer of the ducts or lobules, it is called?invasive or infiltrating carcinoma. This is a true breast cancer, in which the tumor cells can spread (metastasize) to other parts of the body.

Types of CIS

The 2 main types of CIS of the breast are:

DCIS and LCIS are diagnosed based on how the cells and tissue look under the microscope, sometimes along with other lab tests. Sometimes both are found in the same biopsy.

In-situ carcinoma with duct and lobular features?means that under the microscope, the CIS looks like DCIS in some ways and LCIS in some ways.

Lobular carcinoma in situ (LCIS)

LCIS is a type of lobular neoplasia, a condition in which cells in the breast lobules grow and multiply more than usual. LCIS is not cancer, but people with LCIS are at an increased risk of breast cancer.

It is unclear whether LCIS is a precancer or if it’s just a general risk factor for developing breast cancer. This is because LCIS generally does not turn into invasive cancer if it’s left untreated. Having LCIS increases a person’s risk of getting breast cancer, but the cancer is just as likely to occur in the breast without LCIS.

Types of LCIS

There are different types of LCIS:

  • Classic LCIS, where the cells lining the lobules of the breast are smaller and are about the same size.
  • Pleomorphic LCIS, where the cells lining the lobules of the breast are larger and look more abnormal.
  • Florid LCIS, where the cells lining the lobules have formed a mass, typically with an area of dead cells in the middle, called central necrosis.

For more information on LCIS, see Lobular Carcinoma In Situ (LCIS).

Does LCIS need to be treated?

Since LCIS is not a true cancer or precancer, often no treatment is needed after the biopsy. But there are times when treatment might be recommended.

After an excisional biopsy

  • If classic LCIS is found, it typically does not need further treatment.
  • If pleomorphic or florid LCIS is found, and margins (edges) don’t contain LCIS cells, it typically does not need further treatment.
  • If pleomorphic or florid LCIS is found, and margins contain LCIS cells, a more extensive surgery may be recommended.

After a needle biopsy

The best way to treat LCIS found on a needle biopsy is not always clear.

For classic LCIS where there are no other concerning features, follow-up with breast exams and imaging tests such as mammograms might be all that is needed.

For pleomorphic or florid LCIS, the doctor will most likely recommend that it be removed completely with an excisional biopsy or some other type of?breast-conserving surgery. An excisional biopsy might also be needed if the abnormal area seen on the mammogram doesn’t look typical for LCIS. If you have LCIS found on needle biopsy, discuss your options with your doctor.

Other considerations

Because LCIS increases your risk of breast cancer later on, close follow-up after a diagnosis of LCIS is important. This increased risk is in both breasts. Your doctor might also talk to you about lifestyle changes or taking medicine to help lower your risk of breast cancer.

Other terms that might be on a pathology report

In addition to LCIS, you might see other medical terms on your pathology report. Many of these are benign changes. Usually, they are not important when seen on a biopsy where there is LCIS.

ADH and ALH?are types of atypical (abnormal) changes in breast cells that can sometimes be seen on a breast biopsy. They aren’t as serious as LCIS. If ADH or ALH is mentioned on your pathology report, talk with your doctor about what these findings might mean for your care.

Other?benign changes that might be noted on a pathology report include:

These aren’t likely to be important if they’re seen on a biopsy sample that also contains LCIS.

Microcalcifications or calcifications are small calcium deposits that can be found in both noncancerous and cancerous breast lesions. They can be seen both on mammograms and under a microscope.

Because certain calcifications can be found in areas containing cancer, their presence on a mammogram might lead to a biopsy of the area. Once the biopsy is done, the pathologist looks at the tissue removed to be sure that it contains calcifications. If the calcifications are there, the doctor knows that the biopsy sampled the correct area (the abnormal area on the mammogram).

When the area of LCIS and some surrounding normal breast tissue is removed, the margins (edges) of the specimen are coated with ink. This helps the pathologist tell whether the abnormal area was removed completely when looking at it under a microscope. If LCIS is touching the ink, called positive margins, it can mean that some LCIS cells were left behind.

Having positive margins doesn’t always mean that you will need more treatment. You’re more likely to need further surgery if the LCIS was described as pleomorphic or florid, or if the abnormal area seen on the mammogram doesn’t look typical for LCIS.

If your pathology report shows LCIS with positive margins, your doctor will talk to you about your options.

E-cadherin is a test that might be done to help determine if carcinoma in situ is ductal (DCIS) or lobular (LCIS). The cells in LCIS are usually negative for E-cadherin. If your report doesn’t mention E-cadherin, it means that this test wasn’t needed.

Other tests that might be done to help diagnose LCIS or DCIS include:

  • High molecular weight cytokeratin (HMWCK)
  • CK903, also known as 34betaE12
  • CK5/6
  • p63
  • Muscle specific actin
  • Smooth muscle myosin heavy chain
  • Calponin
  • Keratin

Not all biopsy samples need these tests. Whether or not your report mentions these tests has no bearing on the accuracy of your diagnosis.

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Developed by the 黑料大湿Posts Cancer Society medical and editorial content team with medical review and contribution by the 黑料大湿Posts Society of Clinical Oncology (ASCO).

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Last Revised: May 21, 2026

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