Invasive (or infiltrating) ductal carcinoma

Invasive (or infiltrating) ductal carcinoma

This is the most common type of breast cancer. Invasive (or infiltrating) ductal carcinoma
(IDC) starts in a milk duct of the breast, breaks through the wall of the duct, and grows
into the fatty tissue of the breast. At this point, it may be able to spread (metastasize) to
other parts of the body through the lymphatic system and bloodstream. About 8 of 10
invasive breast cancers are infiltrating ductal carcinomas.
Invasive (or infiltrating) lobular carcinoma
Invasive lobular carcinoma (ILC) starts in the milk-producing glands (lobules). Like IDC,
it can spread (metastasize) to other parts of the body. About 1 invasive breast cancer in
10 is an ILC. Invasive lobular carcinoma may be harder to detect by a mammogram than
invasive ductal carcinoma.
Less common types of breast cancer
Inflammatory breast cancer: This uncommon type of invasive breast cancer accounts
for about 1% to 3% of all breast cancers. Usually there is no single lump or tumor.
Instead, inflammatory breast cancer (IBC) makes the skin on the breast look red and feel
warm. It also may give the breast skin a thick, pitted appearance that looks a lot like an
orange peel. Doctors now know that these changes are not caused by inflammation or
infection, but by cancer cells blocking lymph vessels in the skin. The affected breast may
become larger or firmer, tender, or itchy.


In its early stages, inflammatory breast cancer is often mistaken for an infection in the
breast (called mastitis) and treated as an infection with antibiotics. If the symptoms are
caused by cancer, they will not improve, and a biopsy will find cancer cells. Because
there is no actual lump, it might not show up on a mammogram, which can make it even
harder to find it early. This type of breast cancer tends to have a higher chance of
spreading and a worse outlook (prognosis) than typical invasive ductal or lobular cancer.
For more details about this condition, see our document, Inflammatory Breast Cancer.
Triple-negative breast cancer: This term is used to describe breast cancers (usually
invasive ductal carcinomas) whose cells lack estrogen receptors and progesterone
receptors, and do not have an excess of the HER2 protein on their surfaces. (See the
section, "How is breast cancer diagnosed?" for more detail on these receptors.) Breast
cancers with these characteristics tend to occur more often in younger women and in
African-American women. Triple-negative breast cancers tend to grow and spread more
quickly than most other types of breast cancer. Because the tumor cells lack these certain
receptors, neither hormone therapy nor drugs that target HER2 are effective treatments
(but chemotherapy can still be useful if needed).
Paget disease of the nipple: This type of breast cancer starts in the breast ducts and
spreads to the skin of the nipple and then to the areola, the dark circle around the nipple.

It is rare, accounting for only about 1% of all cases of breast cancer. The skin of the
nipple and areola often appears crusted, scaly, and red, with areas of bleeding or oozing.
The woman may notice burning or itching.
Paget disease is almost always associated with either ductal carcinoma in situ (DCIS) or
infiltrating ductal carcinoma. Treatment often requires mastectomy. If no lump can be felt
in the breast tissue, and the biopsy shows DCIS but no invasive cancer, the outlook
(prognosis) is excellent. If invasive cancer is present, the prognosis is not as good, and
the cancer will need to be staged and treated like any other invasive cancer.
Phyllodes tumor: This very rare breast tumor develops in the stroma (connective tissue)
of the breast, in contrast to carcinomas, which develop in the ducts or lobules. Other
names for these tumors include phylloides tumor and cystosarcoma phyllodes. These
tumors are usually benign but on rare occasions may be malignant.
Benign phyllodes tumors are treated by removing the tumor along with a margin of
normal breast tissue. A malignant phyllodes tumor is treated by removing it along with a
wider margin of normal tissue, or by mastectomy. Surgery is often all that is needed, but
these cancers might not respond as well to the other treatments used for more common
breast cancers. When a malignant phyllodes tumor has spread, it can be treated with the
chemotherapy given for soft-tissue sarcomas (this is discussed in detail in our document,
Sarcoma - Adult Soft Tissue Cancer.
Angiosarcoma: This form of cancer starts in cells that line blood vessels or lymph
vessels. It rarely occurs in the breasts. When it does, it usually develops as a complication
of previous radiation treatments. This is an extremely rare complication of breast
radiation therapy that can develop about 5 to 10 years after radiation. Angiosarcoma can
also occur in the arms of women who develop lymphedema as a result of lymph node
surgery or radiation therapy to treat breast cancer. (For information on lymphedema, see
the section, "How is breast cancer treated?") These cancers tend to grow and spread
quickly. Treatment is generally the same as for other sarcomas. See our document,
Sarcoma - Adult Soft Tissue Cancer.