About LCIS

LCIS (lobular carcinoma in situ) is a condition where abnormal cells form in the inner lining of the breast lobules. These abnormal cells look like cancer cells, but they are contained in the lobules. They have not spread into your breast tissue or other parts of the body (the term in situ means ‘in place’).

LCIS is not life-threatening, but you may need treatment. Having LCIS may increase your risk of developing an invasive breast cancer later on in life.

You may develop LCIS in one or both breasts. Men can develop LCIS, but this is very rare.

Is LCIS the same as breast cancer?

It is important to note that doctors do not consider LCIS to be ‘breast cancer’. The condition is a breast change. It is not life-threatening.

LCIS and another type of breast change (‘atypical lobular hyperplasia’) are types of lobular neoplasia. They are non-cancerous (‘benign’), but both increase your risk of breast cancer.

Most women with LCIS will not get breast cancer.

Types of LCIS

There are different types of LCIS. The type determines whether you need any treatment.

Classic LCIS

Most people with LCIS have the ‘classic’ type.

The abnormal cells are small and similar in size. Breast cancer is unlikely to develop from classic LCIS cells.

If you do not have any other abnormal changes in the breast, you usually do not need any treatment. This is because LCIS is confined inside the breast lobule.

Even without treatment, classic LCIS does not usually spread beyond the lobule and become invasive breast cancer.

Pleomorphic LCIS and florid LCIS

In pleomorphic LCIS, the cells are larger and look more abnormal than classic LCIS.

In florid LCIS, the cells have formed a mass with an area of dead cells in the middle (‘necrosis’).

Both pleomorphic and florid LCIS may show up on a mammogram. 

It is likely your doctor will recommend treatment including surgery.

Symptoms and diagnosis of LCIS

LCIS doesn’t normally cause symptoms. You can’t usually feel it as a breast lump, and it does not show up on a mammogram. 

A biopsy is part of the process to diagnose LCIS. Usually this is a 'core biopsy’, which uses a needle to take samples of tissue. Sometimes it may be an (‘excision biopsy’) - an operation to remove a sample of tissue.

This allows them to check for cancer cells in that part of the breast.

They may also use mammogram and ultrasound to find the exact area.

Talk to your doctor about the tests you might need and what they involve. 

About breast lobules

Lobules are the glands that make breast milk. The lobules are found in clusters (like a bunch of grapes) at the end of the milk ducts in the breast.