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 cancer	Proportion of all invasive breast cancers	Tumor characteristics	Prognosis
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 carcinoma	1-5%*	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) carcinoma	2%	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 features	Less than 1%	Soft tumor Cells have a sheet-like appearance Tumors are typically ER-negative, PR-negative and HER2-negative (often called triple negative)	More common among younger women and women with a BRCA1 gene mutation
Invasive papillary carcinoma	Less 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.

 

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.