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 (so the breast often looks inflamed).

About 1-5 percent of breast cancers are 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 1-3 percent of breast cancers are Paget disease of the breast.

Fewer than 1 percent of invasive breast cancers are metaplastic breast cancers.

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

• Be larger
• Have a higher tumor grade

Compared to more common types of breast cancer, they are also more likely to be triple negative.

Triple negative breast cancers are:

• Estrogen receptor-negative
• Progesterone receptor-negative
• HER2-negative

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 another pathologist 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.  

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

Other types of tumors in the breast can be benign (not cancer) or malignant (cancerous).

Because these cancers are not carcinomas, treatment is different than treatment for breast cancer.

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