Rare types of breast cancer
Breast cancer is the most common cancer in the UK. The most common type is invasive breast cancer No Special Type (NST).
There are other rare types of breast cancer. Find out about some of these and how they are treated.
Grouping breast cancers
Doctors have developed ways of grouping breast cancers into different types. They sometimes call rarer breast cancers special type, and the more common breast cancers no special type.
Most invasive breast cancers have no special features and are classed as No Special Type (NST) or not otherwise specified (NOS). Between 70 and 80 out of 100 breast cancers (between 70 and 80%) are this type.
Special type breast cancers have cells with particular features. These are seen when the doctor looks at the cells under the microscope.
Less than 1 in 5 out of every 100 breast cancers (less than 5%) are medullary breast cancers. They occur more often in younger women and in women who have inherited a faulty 
.
The cancer cells tend to be bigger than in other types of breast cancer. When doctors look at these cancers under a microscope they can see a clear boundary between the tumour and the normal tissue. This type of breast tumour is also unusual because it contains .
Medullary breast cancers tumours are generally triple negative. This means that the cancers don’t have for , , or . So hormone therapy or targeted therapy isn't helpful for these cancers.
Doctors treat medullary breast cancer in the same way as other types of invasive breast cancer, with surgery, radiotherapy, and drug treatment. The outlook is generally very good.
Between 1 to 2 out of every 100 breast cancers (between 1 to 2 %) are mucinous breast cancers. This type of cancer tends to be slower growing than other types and occurs more often in older women. It is less likely to spread to the .
Mucinous breast cancers have this name because the cancer is made up of a large amount of mucin. It can be a pure mucinous cancer or it can be a mix of mucinous and other types.
Doctors usually treat mucinous cancers in the same way as other types of breast cancer. They remove the cancer with surgery, either taking away the whole breast (mastectomy) or part of the breast (breast conserving surgery). You might have a biopsy to see if the cancer has spread to the lymph nodes.
The outlook for mucinous breast cancer is generally very good.
About 2 out of every 100 breast cancers (about 2%) are the tubular type. The cancer cells look like tubes when seen under a microscope. This type occurs more often in older women and the tumour is usually very small when diagnosed. It sometimes spreads to nearby .
Treatment is the same as for other types of invasive breast cancer. Tubular breast cancer is less likely to come back after treatment than some other types. So, the outlook is generally good.
Less than 1 in 100 breast cancers (less than 1%) are adenoid cystic cancer. It is a cancer type that is more often diagnosed in the salivary glands, but some develop in the breast tissue.
It is often diagnosed in people in their 50's and 60's.
Adenoid cystic breast cancer tends to be slow growing. Doctors usually recommend surgery. Most women don’t need to have the whole breast removed (a mastectomy). Instead, your doctor will just remove the area of the cancer. This operation is called breast conserving surgery.
The cancer rarely spreads elsewhere in the body. So you don't usually need to have your removed. The risk of this type of tumour coming back is low, so the outlook is good.
This type of breast cancer is very rare and makes up less than 5 out of 100 breast cancers (less than 5%). It usually occurs over 50 years of age and is relatively more common in Hispanic or black women.
Doctors treat metaplastic cell cancers in the same way as other breast cancers. You might have surgery, chemotherapy and radiotherapy.
Some metaplastic breast tumours are triple negative. This means that the cancers don’t have for , , or . So hormone therapy or targeted therapy isn't helpful for these cancers.
Metaplastic breast cancer tends not to spread to the . But it is more likely to spread to other parts of the body than other types of breast cancer.
Non-Hodgkin lymphomas (NHL) of the breast are rare and make up less than 1 in 100 breast cancers (less than 1%).
The most common types are B-cell lymphomas such as diffuse large B-cell lymphomas and extranodal marginal zone lymphomas. A less common type is peripheral T-cell lymphoma (PTCL).
There is a rare type of NHL called breast implant associated anaplastic large cell lymphoma (BIA-ALCL). This can develop in a small number of women who have breast implants. The first sign is usually a swelling (seroma) around the breast implant. Very rarely, a lump may be felt close to the implant.
For most people these symptoms happen many years after their implant surgery, but it could happen sooner. An in situ BIA-ALCL is when the lymphoma hasn’t spread into other areas of the breast. The implant is removed and no further treatment is usually needed, but sometimes you may have drug treatment. The outlook is excellent for this type.
In some women the lymphoma can show as a lump in the breast. This type is called infiltrative i-ALCL and it might also spread to the . After removing the implant, the treatment is usually chemotherapy or sometimes radiotherapy. The outlook is not so good for this type.
Basal type breast cancer has particular changes in the cells. The cells make large amounts of a protein called cytokeratin 5/6.
Basal type breast cancers are often triple negative. This means that they don't have many for , , or . So, hormone therapies and targeted drugs don't work for most basal type cancers.
Doctors use other treatments, such as surgery, chemotherapy and radiotherapy, instead.
Phyllodes is pronounced fill-oy-dees. This type of breast cancer makes up less than 1 in 100 breast cancers (less than 1%). It’s also called cystosarcoma phyllodes. The first symptom is usually a lump in the breast.
Phyllodes can be either cancerous (malignant) or non cancerous (benign). It tends to occur in middle aged women or older. If cancerous, it might spread into the but this is rare.
Surgery is the main treatment. Sometimes you might also have radiotherapy or chemotherapy.
Papillary breast cancer makes up less than 1 in 100 breast cancers (less than 1%). Papillary tumours tend to affect older women.
There are different types of papillary breast cancer:
- in-situ, these are early stage cancers that have not spread
- invasive, these have spread to or beyond surrounding breast tissue
- non cancerous (benign), these are also called papilloma’s
Treatment depends on the type of papillary breast cancer. You may have surgery to the breast and sometimes the . You may also have radiotherapy and drug treatment.
Angiosarcomas of the breast are a type of breast sarcoma. Less than 1 in 100 breast cancers (less than 1%) are breast sarcomas. They start in the cells that make up the walls of the blood vessels or .
Breast angiosarcomas are divided into:
- primary breast angiosarcoma
- secondary breast angiosarcoma
Primary breast angiosarcoma usually develops in younger women in their 30s or 40s. Secondary angiosarcomas are also called treatment related breast sarcomas. They usually develop in older women after having radiotherapy to the breast for a previous breast cancer.
Angiosarcomas tend to grow quickly and spread to other parts of the body such as the lungs and liver. Treatment is usually surgery to remove the whole breast (mastectomy). After surgery, you might have radiotherapy.
Coping with a rare type of breast cancer
Coping with a diagnosis of cancer can be difficult, both practically and emotionally. It can be especially difficult if you have a rare cancer. Being well informed about your cancer and its treatment can make it easier to make decisions and cope with what happens.
Talking to other people who have the same thing can help. But it can be hard to find people who have had a rare type of cancer.
There are things you can do, people who can help and ways to cope with a diagnosis of cancer.
Cancer Chat is Cancer Research UK’s discussion forum. It is a place for anyone affected by cancer. You can share experiences, stories and information with other people who know what you are going through.
Support and information
There are rare cancer organisations that provide support and information, these include:
The Rare Cancer Alliance
The Rare Cancer Alliance offer support and information to people affected by rare cancers. It has a forum where you might be able to meet others with the same cancer as you.
RareCan
RareCan allows people with rare cancer types to share their information with researchers. By doing this they hope to speed up the finding of new treatments and ways to diagnose people with rare cancer. RareCan also allows people to connect with other people who have a rare cancer.
EURACAN
EURACAN connects patients who have rare adult solid cancer to expert health care centres across Europe.
Cancer 52
This is an alliance of 90 organisations working to address inequality in funding for rare cancers and improving outcomes for patients.
Email : info@cancer52.org.uk
Finding information on rare breast cancers
It can be hard to find useful information about a rare type of cancer. Ask your doctor or specialist nurse if they know of any suitable information. You could ask about the best term to use if you want to look for information online.
You can also contact our Cancer Research UK information nurses. They can give advice about who can help you and what kind of support is available. Freephone: 0808 800 4040 - Monday to Friday, 9am to 5pm.
Research and clinical trials
There may be fewer clinical trials for rare types of cancer than for more common types. It is hard to organise and run trials for rare cancers. Getting enough patients is critical to the success of a trial. The results won't be powerful enough to prove that one type of treatment is better than another if the trial is too small.
The International Rare Cancers Initiative (IRCI) aims to develop more research into new treatments for rare cancers. They are designing trials that involve several countries so that more people will be available to enter trials.
