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

When biopsy samples are collected from your breast, they are studied by a doctor with special training, called a pathologist. After testing the samples, the pathologist creates a report on what was found. Your doctors can use this report to help manage your care. 

The information here is meant to help you understand some of the medical terms you might see in your pathology report after a breast biopsy, which might be a needle biopsy or a surgical (open) biopsy. 

In a needle biopsy, a hollow needle is used to remove samples from an abnormal area in your breast. In some situations, a surgical biopsy might be needed. This can be either an incisional biopsy, in which only part of an abnormal area is removed, or an excisional biopsy, which removes the entire abnormal area, often with some of the surrounding normal tissue. An excisional biopsy is much like a type of breast-conserving surgery called a lumpectomy. 

What is in-situ carcinoma (or carcinoma in situ) of the breast? 

A carcinoma is a cancer that begins in the lining layer (epithelial cells) of organs like the breast. Nearly all breast cancers are carcinomas.

In-situ carcinoma (also known as carcinoma in situ, or CIS) is a term is used when cells that look like cancer cells are growing in the lining layer of cells but they don’t invade through the wall.

The normal breast is made of tiny tubes (ducts) that end in a group of sacs (lobules), which is where milk is made. Breast cancer typically starts in the cells lining the ducts or lobules, when a normal cell becomes a carcinoma cell. As long as the carcinoma cells are still confined to the breast ducts or lobules and do not grow into deeper layers, it is considered in-situ carcinoma (also known as carcinoma in situ, or CIS). 

If the carcinoma cells have grown beyond 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. 

Lobular carcinoma in situ (LCIS), lobular neoplasia, or in-situ carcinoma with duct and lobular features 

The 2 main types of in-situ carcinoma of the breast are:

DCIS and LCIS are diagnosed based on how the cells and tissue look under the microscope, and sometimes both are found in the same biopsy. 

LCIS and another type of breast change called atypical lobular hyperplasia (ALH)  are types of lobular neoplasia. These are benign (non-cancerous) conditions, but they both increase your risk of breast cancer.

In-situ carcinoma with duct and lobular features means that the in-situ carcinoma looks like DCIS in some ways and LCIS in some ways (under the microscope), so the pathologist can’t call it one or the other.

Lobular carcinoma in situ (LCIS) is a type of in-situ carcinoma of the breast. While DCIS is considered a pre-cancer, it is unclear whether LCIS is a pre-cancer or if it’s just a general risk factor for developing breast cancer. This is because LCIS rarely seems to turn into invasive cancer if it’s left untreated. Having LCIS does increase a person’s risk of getting breast cancer, but the cancer occurs just as often in the opposite breast (the one without any LCIS). Because it isn't clear if LCIS is a pre-cancer, many doctors prefer to use the term lobular neoplasia instead of lobular carcinoma in situ.

 There are different types of LCIS:

  • Classic LCIS: The cells lining the lobules of the breast are smaller and are about the same size.
  • Pleomorphic LCIS: The cells lining the lobules of the breast are larger and look more abnormal.
  • Florid LCIS: The cells lining the lobules have grown into a large enough group that they have formed a mass, typically with an area of dead cells in the middle (called central necrosis).

If classic LCIS is found by an excisional biopsy, it typically does not need further treatment. However, with pleomorphic or florid LCIS, it’s important that the edges (margins – see below) of the biopsy specimen don’t contain LCIS cells (which might mean that some were left behind). If they do, the doctor may recommend a more extensive surgery to make sure all of it was removed.

The best way to treat LCIS found on a needle biopsy is not 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 found on needle biopsy, 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 may 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. 

Because LCIS increases a person’s risk of breast cancer later on, your doctor might talk to you about lifestyle changes and/or taking medicine to lower your risk of breast cancer

If, in addition to LCIS, the report also mentions atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH)…

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

If, in addition to LCIS, the report also mentions benign (non cancerous) changes such as...

  • Usual ductal hyperplasia
  • Adenosis
  • Sclerosing adenosis
  • Radial scar
  • Complex sclerosing lesion
  • Papillomatosis
  • Papilloma
  • Apocrine metaplasia
  • Cysts
  • Columnar cell change
  • Collagenous spherulosis
  • Duct ectasia
  • Fibrocystic changes
  • Flat epithelial atypia
  • Columnar alteration with prominent apical snouts and secretions (CAPSS) 

All of these are benign (non-cancerous) changes that the pathologist might see. Usually, they are not important when seen on a biopsy where there is LCIS.

Microcalcifications or calcifications

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

Because certain calcifications can be found in areas containing cancer, their presence on a mammogram may 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).

Margins or ink

When the entire area of LCIS (and some surrounding normal breast tissue) is removed, the outside surface (edges or margins) of the specimen is coated with ink, sometimes even with different colors of ink on different sides of the specimen. This helps the pathologist know which edge of the specimen they’re looking at.

The pathologist looks at slides of the LCIS to see how close the LCIS cells are to the ink (the edges or margins of the specimen). If LCIS is touching the ink (called positive margins), it can mean that some LCIS cells were left behind. Sometimes, though, the surgeon has already removed more tissue (during surgery) to help make sure that this isn’t needed.

Still, since LCIS doesn’t usually turn into invasive cancer, having positive margins doesn’t automatically mean that you will need more treatment. In fact, you may only need further surgery if the LCIS was described as pleomorphic or florid, or if the LCIS caused a lump that could be felt or seen as a tumor on a mammogram.

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

E-cadherin

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 to make the distinction.

Other lab tests that might be done

  • High molecular weight cytokeratin (HMWCK)
  • CK903
  • CK5/6
  • p63
  • Muscle specific actin
  • Smooth muscle myosin heavy chain
  • Calponin
  • Keratin 

These are special tests that might be done to help diagnose LCIS (or DCIS). Not all biopsy samples need these tests. Whether or not your report mentions these tests has no bearing on the accuracy of your diagnosis. 

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Last Revised: July 7, 2023

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