Types of breast cancer and related breast conditions
The breast is made up of a series of branching tubes called ducts. The ducts start at the nipple and end in small glands called terminal duct lobular units (TDLU). The TDLU has 2 parts:
the extra lobular terminal duct
the lobule
The TDLU are responsible for making breast milk after pregnancy.
LCIS is when the terminal duct lobular units of the breast fill with abnormal cells.
The abnormal cells stay in the ducts and can’t spread into the surrounding breast tissue. This is different to invasive breast cancer where the abnormal cells have broken through the ducts. LCIS can be found in both breasts.
Although LCIS isn’t cancer, it means that you have a small increased risk of getting invasive breast cancer in either breast in the future. Even so, most women with LCIS won't develop breast cancer. Men can develop LCIS but this is very rare.
You might hear you doctor call LCIS a type of lobular neoplasia. Neoplasia means abnormal cells. Atypical lobular hyperplasia is another type of lobular neoplasia. It is very similar to LCIS but with fewer abnormal looking cells.
Find out about atypical hyperplasia in a breast lump
Around 745 people are diagnosed with LCIS each year in the UK.
LCIS doesn't usually show up on breast x-rays (mammograms), and it normally doesn't cause symptoms. It's often diagnosed by chance during tests for other breast conditions, such as a biopsy.
There is a type of breast cancer called invasive lobular breast cancer. This is different to LCIS.
Read about invasive lobular breast cancer
Treatment for LCIS depends on the type you have. There are 3 main types of LCIS:
classic LCIS (CLCIS)
pleomorphic LCIS (PLCIS)
florid LCIS (FLCIS)
Most people with CLCIS do not need to have any treatment. But your doctor may take more breast tissue if you had a core biopsy. This is to check the area for any other changes. To remove more breast tissue you might have surgery or a vacuum assisted biopsy using a mammogram or ultrasound scan.
Find out more about having a breast biopsy
You usually have regular monitoring. In some situations, your doctor may offer you hormone therapy or surgery to keep your risk of developing invasive breast cancer low.
Some rarer types of LCIS such as pleomorphic LCIS or florid LCIS, are treated in a similar way to DCIS.
Your doctor might suggest that you have regular monitoring because there is an increased risk of breast cancer. They might call this close observation or careful observation.
You might have a breast x-ray (mammogram) every year for 5 years.
If a cancer does develop, the monitoring should pick it up at a very early stage. Then you can have the treatment you need as early as possible.
You are more likely to have surgery rather than monitoring if you have a particular type of LCIS called pleomorphic LCIS or florid LCIS.
You might have breast conserving surgery (a wide local excision) to remove the LCIS and a surrounding area of normal tissue. Rarely you have surgery to remove your breast (a mastectomy). You might have this if the changes are widespread throughout the breast.
Get information about treatments for LCIS and breast cancer
Your doctor may discuss hormone therapy with you. This depends on your situation. Some people take hormone therapy for 5 years to lower the risk of developing invasive breast cancer. This is called chemo prevention.
Many breast cancers are stimulated to grow by the female oestrogen and progesterone. These breast cancers are called hormone sensitive or hormone receptor positive.
Hormone therapy works by lowering the levels of these hormones in the body or blocking their effects.
The hormone therapy you have will depend on if you have had the or not. Hormone therapy drugs include:
tamoxifen
anastrozole
raloxifene
exemestane
Find out more about these from our cancer drugs A to Z list
Doctors and researchers are carrying out trials to find better tests and treatments for breast cancer and other conditions such as Paget’s disease.
Last reviewed: 22 May 2026
Next review due: 22 May 2029
You have a number of tests to check for breast cancer. This includes a breast examination, a mammogram, a biopsy and scans.
Treatment for LCIS and breast cancer depends on a number of factors. Find out about breast cancer treatments, where and how you have them, and how to cope with possible side effects.
Invasive lobular breast cancer is the second most common type of breast cancer. It's also known as invasive lobular carcinoma.
There are different types of breast cancer and breast conditions, including breast cancer in men, and conditions related to breast cancer.
Breast cancer is cancer that starts in the breast tissue. It’s the most common cancer in the UK. It mainly affects women, but men can get it too.
Find out about breast cancer, including symptoms, diagnosis, treatment, survival, and how to cope with the effects on your life and relationships.
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