Invasive lobular carcinoma is a type of cancer that starts in the milk glands of the breast and spreads easily to surrounding tissue. It most commonly affects women, but it can also occur in men.

Another name for invasive lobular carcinoma is “infiltrating lobular carcinoma.” Around 10% of people with a diagnosis of invasive breast cancer will have this type.

In 2015, researchers noted that invasive lobular carcinoma might account for up to 15% of all breast cancers. Around two-thirds of cases affect women aged 55 years and over.

As the name suggests, invasive lobular carcinoma frequently spreads out of the milk gland (lobule) where it forms and may invade and infect other lymph nodes.

It is similar to other invasive breast cancers in that it can spread easily to other parts of the body. However, unlike other breast cancers, it does not cause a lump.

Since it does not usually involve a lump, invasive lobular carcinoma can be harder for the individual to spot than other types of breast cancers.

Also, invasive lobular carcinoma is more challenging to detect than other breast cancers through traditional breast cancer screenings methods, using mammograms and ultrasounds.

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Symptoms can include discomfort in the breast.

In the earliest stages, invasive lobular carcinoma may not cause any signs or symptoms. However, as the cancer progresses, the following may occur:

  • thickening or other palpable mass in parts of the breast
  • a newly inverted nipple
  • swelling in part of the breast
  • changes in skin texture of the breast
  • a lump under the armpit
  • redness or scaliness in the breast skin
  • pain or irritation in the breast or nipple
  • discharge from the nipple that is not breast milk

A breast lump can be a sign of cancer, but it is not the only one. Find out more about the other symptoms that can occur.

Tests to investigate invasive lobular carcinoma include the following:

Mammogram: An X-ray of the breast may show some changes, but a doctor will usually recommend another test alongside this, as mammograms are not good at detecting invasive lobular carcinoma.

Ultrasound: An ultrasound scan can show changes in the internal breast tissues, but these scans are not always effective at detecting invasive lobular carcinoma.

MRI: This may help detect cancer if the results of other tests are unclear. It can also show how much of the breast cancer has affected and how far it may have spread.

Biopsy: This involves removing and testing a sample of breast tissue. A biopsy can be through surgery or a needle extraction. A biopsy can confirm the diagnosis of invasive lobular carcinoma and identify the type.

Together with a physical examination and blood tests, these tests can usually confirm whether someone has invasive lobular carcinoma, whether it has spread, and, if so, how far.

Knowing how much cancer has invaded will also indicate which stage it has reached. In the early stage, it will only affect the breast tissue. In the late stage, cancer will have spread to other organs in the body, such as the lungs.

There are several kinds of invasive lobular carcinoma, depending on how the cancer cells look under the microscope.

The most common type consists of small cells that invade the fatty tissues and ligaments around the milk ducts. In these classic cases of invasive lobular carcinoma, the cancer cells look similar to each other and grow in a single file pattern.

Doctors classify other types according to their growth pattern.

They include:

Solid invasive lobular carcinoma: The cancer cells grow in large sheets with little healthy tissue between them.

Alveolar invasive lobular carcinoma: Cancer cells grow in groups rather than in a singular pattern.

Tubulolobular invasive lobular carcinoma: This shows some of the growth patterns of classic invasive lobular carcinoma, but some cells also form small tube-like structures, known as tubules.

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The doctor will ask about symptoms and carry out some tests.

There are various treatment options for breast cancer, including invasive lobular carcinoma.

It can be hard to determine the extent of the cancer, and it often needs aggressive treatment. Surgical treatment is common.

The doctor may recommend different combinations of treatment, depending on factors such as:

  • how aggressive the cancer is
  • how far it has spread and the stage
  • a person’s overall health and previous medical history
  • personal preference

Options include surgery, medication, and radiation therapy.


Surgical options include:

Lumpectomy: A surgeon removes a small portion of the breast.

Mastectomy: The surgeon removes all the breast tissue, including some healthy tissue surrounding the cancer.

The decision will vary between individuals. It will depend largely on the stage of the cancer and how aggressive it has become.

Learn more about the different types of mastectomy and what they involve.


Radiation therapy can target the area where cancer occurs. Radiation therapy aims a high-powered, focused beam of radiation directly at any areas that cancer is affecting.

Doctors will typically recommend it alongside surgery for treating invasive lobular carcinoma.


Chemotherapy uses powerful drugs to kill cancer cells. It is a systemic medicine, which means it affects the whole body.

Like radiation, chemotherapy is not normally the first course of action for invasive lobular carcinoma. However, a doctor may prescribe it to shrink an area of cancer before surgery or to kill any cancer cells that remain after surgery.

Hormone therapy

Up to 95% of invasive lobular carcinomas are hormone-receptor positive.

This means that the cancer may respond to hormone therapy. In some types of cancer, hormonal activity or features encourage the cancer cells to grow. Stopping the hormones from having this effect can slow or stop the progression of cancer in these cases.

Before beginning hormone therapy, a doctor will carry out a test to see if specific hormone receptors are present on the cancer cells. If they are, the person may receive treatment that prevents the cancer from using circulating hormones to grow and spread.

A doctor normally recommends combining hormone therapy with surgery to treat invasive lobular carcinoma.

Targeted therapy

Similarly to hormone therapy, targeted therapy attacks specific features in the body. It uses drugs or other substances to destroy specific cells or parts of cells without harm to normal ones.

If a person’s cancer may be due to genetic mutations, for example, in the BRCA1 or BRCA2 genes, a doctor may recommend targeted therapy that prevents the activity of these genes that promote cancer growth.

The outlook for a person with invasive lobular carcinoma will depend largely on the type of cancer that is present, whether or not it has spread, the activity of hormone receptors, response to treatment, and the person’s age.

A person will have a better chance of effective treatment if they have an early diagnosis and early treatment.

Similarly, in most cases, earlier diagnosis and treatment mean a better outlook.


How often does a person get an early diagnosis for this kind of cancer? Is it usually fatal?


Early diagnosis for this type of breast cancer is not common. It’s difficult to image, especially if you have dense breasts, and it doesn’t always form lumps. In general, people often discover lobular tumors at a later stage.

However, one’s outlook is dependent on the stage, subtype, and variant of the cancer, as well as the individual’s biological profile that influences his or her response to treatment.

Christina Chun, MPH Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.