Types of Tumors

Although breast cancer is often referred to as one disease, there are actually many different types of breast cancer. All breast cancers start in the breast, so they are alike in some ways, but differ in others. They can be non-invasive or invasive. And, the tumor cells can vary in location (ducts or lobules) and how they look under a microscope. These differences often affect prognosis.

Tumor characteristics, such as hormone receptor status and HER2/neu status, can also affect prognosis. Learn more about these tumor characteristics.   

Non-invasive and invasive breast cancers    

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 inthe milk ducts ofthe breast and have not spread into the surrounding breast tissue. (For more on breast structure, see Figure 1.1).

Although DCIS is non-invasive, without treatment, the abnormal cells could turn into invasive breast cancer over time. So, you may also hear the term pre-invasive breast carcinoma to describe DCIS.

Learn more about DCIS.   

Invasive breast cancer

Invasive breast cancer has spread from the original site (either the milk ducts or the lobules) into the surrounding breast tissue and possibly spread to the lymph nodes and/or other parts of the body. For this reason, invasive breast cancers have a poorer prognosis than DCIS.

Using a microscope to look at the tissue removed during a biopsy, a pathologist can determine whether a tumor is DCIS or invasive breast cancer.   

Types of invasive breast cancer

Figure 4.6 lists the types of invasive breast cancer. The most common type is invasive ductal carcinoma (also called infiltrating ductal carcinoma and less commonly, invasive carcinoma of no special type or invasive carcinoma not otherwise specified). Invasive ductal carcinoma accounts for 50 to 75 percent of all breast cancers [17].

Invasive lobular carcinoma is the next most common type and accounts for about 10 to 15 percent of cases [17].

Tubular carcinoma and mucinous (colloid) carcinoma are less common types of invasive breast cancer that tend to have a good prognosis [8,17].  

Special forms of breast cancer

Though they are not specific types of tumors, there are some special forms of breast cancer. These include inflammatory breast cancer (IBC), Paget disease of the breast (Paget disease of the nipple) and metaplastic breast cancer and are discussed below.   

Inflammatory breast cancer (IBC)  

What is inflammatory breast cancer?  

Inflammatory breast cancer (IBC) is a rare, but aggressive form of locally advanced breast cancer. It is called inflammatory breast cancer because its main symptoms are swelling (inflammation) and redness of the breast.

IBC tumors are often estrogen receptor-negative and HER2/neu-positive. Because these breast cancers are aggressive, most women with IBC have positive lymph nodes and 25 to 30 percent have metastasis when they are diagnosed [19]. IBC also tends to have a higher proliferation rate than other breast cancers [19].

The average age of diagnosis of IBC is slightly younger than the age of diagnosis of other breast cancers [19]. African American women may be somewhat more likely than white women to be diagnosed with IBC [20].

IBC myth 

Although some viral e-mails suggest that IBC is a new form of breast cancer, it was first identified in the 1800’s [19].

Symptoms of IBC  

Symptoms of IBC include [19]: 

• Swelling or enlargement of the breast
• Redness of the breast (may also be a pinkish or purplish tone)
• Dimpling or puckering of the skin of the breast
• Pulling in of the nipple
• Breast pain
• Although sometimes a lump can be felt, it is less common with IBC than with other breast cancers 

If you notice any of these changes, see your health care provider. 

Diagnosis of IBC  

With other forms of breast cancer, symptoms may not occur for years. However, with IBC, symptoms tend to arise within weeks or months. Because of the frequent lack of a breast lump and symptoms such as redness and swelling, IBC may first be mistaken for an infection. IBC is often diagnosed clinically with a tissue biopsy after symptoms do not improve with a course of antibiotics.

Routine mammography can miss IBC because of its rapid onset. IBC can also be hard to see on a mammogram because it is often spread throughout the breast or may only show up as a sign of inflammation (such as skin thickening) [19]. In some cases, skin changes (listed above) or a lump (if one is present) may be noted during a clinical breast exam.  

Survival rates of IBC  

With treatment, up to 65 percent of those with IBC will live for five years after diagnosis and about 35 percent will be cancer-free 10 years after diagnosis [22-25]. Although these rates are not as high as for other breast cancers, new treatments continue to improve survival.  

Learn about treatment for IBC.  

Paget disease of the breast (Paget disease of the nipple)

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. It is usually, but not always, found with an underlying breast cancer. In these cases, the tumor grows from underneath the nipple and breaks out onto the skin surface of the nipple. Paget disease of the breast can be found with invasive breast cancer or DCIS.

Symptoms include itching, burning, redness and scaling of the skin on the nipple and areola. There may also be a bloody discharge from the nipple, and the nipple may appear flattened against the breast [18].

Paget disease of the breast can be diagnosed from a biopsy of the nipple skin and the tissue just below the skin (called a skin biopsy or a punch biopsy). Or, Paget disease of the breast may be found when an underlying breast cancer is diagnosed. Treatment and prognosis depend on the underlying cancer [18].  

Metaplastic breast cancer

Metaplastic breast cancer is rare, accounting for fewer than five percent of all invasive breast cancers [17]. Compared to more common types of breast cancer, metaplastic tumors tend to be larger, have a higher tumor grade and be estrogen receptor-negative, progesterone receptor-negative and HER2/neu receptor-negative (often called triple negative) [17,26-27].

Because metaplastic tumor cells have many forms, these cancers can be hard to diagnose and are often confused with other uncommon breast tumors. It is best to have the pathology slides sent out for review to confirm the diagnosis. You can request that your health care provider send the slides out for review or you may wish to get a second opinion for confirmation. 

Learn more about breast pathology practices.

Learn more about getting a second opinion.  

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. Rarely, cancers from other sites can metastasize (spread) to the breast and mimic breast cancers.

Other types of tumors in the breast can be benign (non-cancerous) or malignant (cancerous). Because these cancers are not carcinomas, they are treated differently and have different risk profiles than breast cancer.

For more information on malignant phyllodes tumors and lymphomas, visit the National Cancer Institute's website.

For more information on benign phyllodes tumors, visit the Breast Facts section.

Updated 04/22/13

Tumor Grade	Tumor Characteristics
	Triple Negative Breast Cancer