The Who, What, Where, When and Sometimes, Why.

Types of Tumors

Although breast cancer is often referred to as one disease, there are many different types of breast cancer.

All breast cancers start in the breast, so they are alike in some ways.

Breast cancers differ in other ways. They can be non-invasive or invasive. Tumor cells can vary in location (milk ducts or lobules) and how they look under a microscope. These differences often affect prognosis.

Tumor characteristics, such as hormone receptor status and HER2 status, also affect prognosis.

Learn more about factors that affect prognosis.

Non-invasive and invasive breast cancers

A pathologist looks at the tissue removed during a biopsy under a microscope to determine whether a tumor is non-invasive (ductal carcinoma in situ) or invasive breast cancer.

Ductal carcinoma in situ (DCIS)

Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer. In situ means “in place.” With DCIS, the abnormal cells are contained in the milk ducts of the breast and have not spread to nearby breast tissue.

Although DCIS is non-invasive, without treatment, the abnormal cells could progress to invasive breast cancer over time. So, you may also hear the terms “pre-invasive” or “pre-cancerous” to describe DCIS.

Learn more about breast anatomy.

Invasive breast cancer

Invasive breast cancer has spread from the original site (either the milk ducts or the lobules) into the nearby breast tissue, and possibly to the lymph nodes and other parts of the body.

For this reason, invasive breast cancers have a poorer prognosis than DCIS.

Types of invasive breast cancer

Figure 4.6 lists the types of invasive breast cancer.

  • Invasive ductal carcinoma is the most common type of breast cancer (70-80 percent of all breast cancers) [17,20]. It may also be called infiltrating ductal carcinoma, invasive carcinoma of no special type or invasive carcinoma not otherwise specified. 
  • Invasive lobular carcinoma is the next most common type (10-15 percent of breast cancers) [17,20]. 
Figure 4.6: Prevalence and Tumor Characteristics of Different Types of Invasive Breast Cancer
Types of invasive breast cancerProportion of all invasive breast cancersTumor characteristicsPrognosis
Invasive ductal carcinoma (IDC)70-80%
  • Hard tumor texture
  • Tumor is irregular, star-shaped
  • Cell features vary
  • DCIS often present

 

  • Prognosis varies with stage and grade of tumor

 

Invasive lobular carcinoma (ILC)10-15%
  • Normal, slightly firm or hard tumor texture
  • Cells most often appear in single file order
  • Tumors are most often ER-positive and HER2-negative

 

  • Prognosis varies with stage and grade of tumor
  • For any given stage or grade, prognosis is similar to that of IDC
  • Pattern of metastases is slightly different from IDC

 

Tubular carcinoma1-5%*
  • Tumors are most often small
  • Often no palpable tumor
  • Cells form tube-like structures
  • Tumors are almost always ER-positive and HER2-negative

 

  • Prognosis is usually
    better than for IDC
  • Rare for cancer to spread to lymph nodes or other parts of the body

 

Mucinous (colloid) carcinoma2%
  • Soft tumor
  • Often no palpable tumor
  • Cells are surrounded by excess mucous (mucin)
  • Tumors are most often ER-positive and HER2-negative

 

  • More common among older women
  • Tends to have a good prognosis
  • Less common for cancer to spread to lymph nodes

 

Carcinomas with medullary featuresLess than 1%
  • Soft tumor
  • Cells have a sheet-like appearance
  • Tumors are typically ER-negative, PR-negative and HER2-negative (often called triple negative)

 

 

Invasive papillary carcinomaLess than 1%
  • Soft tumor
  • Cells appear as fingerlike branches

 

  • More common in women after menopause
  • Tends to have a good prognosis

 

* Percentage is higher in cancers found through mammography screening.
ER-positive = estrogen receptor-positive
ER-negative = estrogen receptor-negative
PR-negative = progesterone receptor-negative
HER2-negative = HER2 receptor-negative
Adapted from select sources [17,20].

Special forms of breast cancer

Though they are not specific types of tumors, some special forms of breast cancer are discussed below.

Inflammatory breast cancer (IBC) is a rare, but aggressive form of locally advanced breast cancer.

It’s called inflammatory breast cancer because its main symptoms are swelling and redness (the breast often looks inflamed).

About 1-5 percent of breast cancers are IBC [21-22].

Learn more about IBC

Paget disease of the breast (Paget disease of the nipple) is a rare cancer in the skin of the nipple or in the skin closely surrounding the nipple.

About 1-4 percent of breast cancers are Paget disease of the breast [23-24].

Learn more about Paget disease of the breast.

Metaplastic breast cancer is rare, accounting for fewer than 1 percent of all invasive breast cancers [25].

Compared to more common types of breast cancer, metaplastic tumors tend to:

They are also more likely to be triple negative [17,25-28]. Triple negative breast cancers are:

Diagnosis

Under a microscope, metaplastic tumor cells can look very different from the tumor cells of more common breast cancers. So, these cancers can be hard to diagnose and are often confused with other uncommon breast tumors or tumors from other parts of the body.

It’s best to have the pathology slides sent out for review to confirm the diagnosis.

You can request your health care provider send the slides out for review or you may wish to get a second opinion for confirmation.

Learn more about getting a second opinion.

 

 SUSAN G. KOMEN® SUPPORT RESOURCES
  • If you or a loved one needs more information about breast health or breast cancer, call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636). All calls are answered by a trained specialist or oncology social worker in English and Spanish, Monday through Friday from 9:00 a.m. to 10:00 p.m. ET. You can also email the helpline at helpline@komen.org.
  • We offer an online support community through our closed Facebook Group – Komen Breast Cancer group. The Facebook group provides a place where those with a connection to breast cancer can discuss each other’s experiences and build strong relationships in order to provide support to each other. Visit Facebook and search for “Komen Breast Cancer group” to request to join the closed group.
  • Komen Affiliates offer breast health education as well as fund breast cancer programs through local community organizations. Your local Affiliate may also help you find other breast cancer resources in your area. Find your local Affiliate
  • Our fact sheets, booklets and other education materials offer additional information. 

 

Other types of cancer that occur in the breast

Most cancers that occur in the breast are breast cancers (breast carcinomas).

In rare cases:

  • Other types of cancer, such as lymphomas (cancer of the lymph system) and sarcomas (cancer of the soft tissues), can occur in the breast.
  • Cancers from other sites can metastasize (spread) to the breast and mimic breast cancers.

Because these cancers are either not carcinomas or are carcinomas that don’t start in the breast, they are treated differently and have different risk factors than breast cancer.

For more information on other cancers that can occur in the breast, such as lymphomas, sarcomas and malignant phyllodes tumors, visit the National Cancer Institute’s website.