Types of Breast Cancer

Breast cancer actually describes a variety of cancers that occur within the breast. Breast cancer is typically categorized by two factors – where the cancerous cells are located and whether the cancer is prone to spreading.

Ductal Carcinoma

Ductal carcinoma is the most common form of breast cancer. It develops in the ducts that carry the milk from the lobules (milk glands) to the nipple. Ductal carcinomas can be either in situ or invasive breast cancer.

Ductal Carcinoma In Situ (DCIS)

In ductal carcinoma in situ, cancer cells are present inside the milk ducts but they have not yet spread through the walls of the ducts into the fatty tissue of the breast. For this reason, nearly 100% of women diagnosed at an early stage can be cured1. The best way to monitor and identify ductal carcinoma in situ is with a yearly mammogram. Left unchecked, it may develop into invasive breast cancer.

Invasive Ductal Carcinoma (IDC)

Invasive ductal carcinoma accounts for nearly 80% of breast cancers2. It also begins in a milk duct, but unlike ductal carcinoma in situ, it invades the fatty tissue of the breast. This invasive carcinoma has the potential to metastasize [meh-TAS-ti-size], or spread to other parts of the body through the bloodstream or lymphatic system. It is important to detect and treat invasive ductal carcinoma before it has had time to metastasize and spread to other organs.

Lobular Carcinoma

Lobular carcinoma is found in the milk-producing glands of the breast. It is far less common than ductal carcinoma, but it can present itself in both breasts more often than other types of breast cancer. Lobular carcinoma can be either in situ or invasive breast cancer.

Lobular Carcinoma In Situ (LCIS)

Technically, lobular carcinoma in situ is not even a cancer. Sometimes called lobular neoplasia [LOB-u-lar nee-o-play-zee-uh], it is classified as pre-cancerous growth that begins in the milk-producing glands. Lobular carcinoma in situ does not penetrate through the wall of the lobules, and most researchers believe it does not usually become an invasive breast cancer. However, women who develop lobular carcinoma in situ have a higher future risk of developing invasive breast cancer in the same or opposite breast. If you have been treated for a lobular carcinoma in situ, you will want to have a physical exam two or three times a year, in addition to an annual mammogram.

Invasive Lobular Carcinoma (ILC)

Similar to invasive ductal carcinoma, invasive lobular carcinoma has the potential to metastasize and spread to other parts of the body. It begins in the milk-producing glands, where it extends into the fatty tissue of the breast. About 10% to 15% of breast cancers are invasive lobular carcinomas3. Invasive lobular carcinoma also can be more difficult to detect by mammogram than LCIS, making it important to have mammograms annually.

Inflammatory Breast Cancer

This rare type of invasive breast cancer accounts for about 1% of all breast cancers4. Inflammatory breast cancer makes the skin of the breast look red and feel warm, as if it were infected. The skin develops a thick, pitted appearance that doctors often describe as resembling an orange peel. Sometimes the breast develops ridges and small bumps that look like hives. Cancer cells blocking lymph vessels or channels in the skin over the breast cause these symptoms.

Medullary Carcinoma

This special type of invasive breast cancer has a relatively well-defined boundary between the tumor tissue and normal tissue. This prevents rapid spreading of the cancer, and it often can be treated more effectively compared to other types of invasive breast cancer. Medullary carcinomas [MED-u-lair-ee kar-sin-OE-ma] account for about 5% of breast cancers5.

Mucinous Carcinoma

Mucinous carcinoma [MYOO-sin-us kar-sin-OE-ma] is another rare type of invasive breast cancer. It is formed in the breast by mucus-producing cancer cells which spread the disease into the surrounding breast tissue. This type of breast cancer is treatable and offers a higher rate of recovery compared with other types of invasive breast cancer.

Paget’s Disease of the Nipple

This type of breast cancer starts in the milk ducts and spreads to the skin of the nipple and areola (the dark circle around the nipple). The nipple and areola will often appear crusted, scaly and red. The patient may experience burning, itching or notice some bloody discharge from the nipple.

Paget’s Disease is a rare form of breast cancer, occurring in only 1% of all cases. It can be associated with in situ carcinoma as well as invasive carcinoma. If no lump can be felt in the breast tissue and the biopsy shows the growth to be in situ and not invasive, treatment for Paget’s Disease is very effective.

Phyllodes Tumor

This rare breast tumor forms from the stroma [STROM-ah] (connective tissue) of the breast, in contrast to carcinomas which develop in the ducts or lobules. Phyllodes [FI-lodes] tumors are usually benign, but on rare occasions have been found to be malignant (cancerous with the potential to metastasize). These occurrences are extremely rare, with fewer than 10 women dying each year as a result of this breast cancer.

Phyllodes tumors do not respond to hormonal therapy and are less likely to respond to other breast cancer treatments such as chemotherapy or radiation therapy. As a result, benign phyllodes tumors are treated by removing the mass and a narrow margin of the surrounding breast tissue. Malignant phyllodes tumors are removed in the same manner with a wider margin of breast tissue, or by mastectomy.

Tubular Carcinoma

Tubular carcinoma [TOOB-u-lar kar-sin-OE-ma] is similar to invasive ductal carcinoma (IDC) and accounts for approximately 2% of all breast cancers. However, the treatment for tubular carcinoma is more effective than that of other invasive breast cancers.

1.,3.,4.,5. https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/types-of-breast-cancer/invasive-breast-cancer.html

2. https://seer.cancer.gov/statfacts/html/breast.html