Types of Cancer > Breast Cancer > Pathology

Breast Cancer Pathology

Infiltrating Ductal Carcinoma
This is the most common type of breast cancer, representing approximately 80% of all diagnoses. Infiltrating or invasive means that the cancer cells have left the lining of the ducts and have begun to form a tumor outside the duct. The cells form a tough scar-like shell that is palpable on examination and visible on mammography.

Infrequently, men develop breast cancer of this type. Approximately 1000 males are diagnosed with this type of breast cancer annually in the United States and receive the same treatment as women.

Treatment requires surgical removal of the tumor: the procedure can be lumpectomy involving less than 25% of the entire breast tissue, or mastectomy, which is the removal of the entire breast. Some lymph nodes are usually removed from the armpit during the surgery and tested for cancer. The surgeon will determine which procedure is best based on the size of the lump and other factors.

Chemotherapy and radiation are considerations following surgery and are determined by the patient and cancer care based on the final pathology report.

Inflammatory Breast Carcinoma
Accounting for only 1-4% of all breast cancers, the diagnosis of inflammatory breast cancer is still a source of great concern to the patient and her physician. The term inflammatory refers to the appearance of the breast. The breast looks red, swollen and is warm to the touch. It is often misdiagnosed as an infection and patients are treated with antibiotics. If the condition remains the same after two weeks of antibiotics, inflammatory breast carcinoma may be indicated. At this point, a biopsy is performed to determine the status of the condition.

As this situation is usually more extensive than other forms of breast cancer the first treatment is often high dose chemotherapy called neoadjuvent treatment because it is done before surgery. Mastectomy is done after four chemotherapy cycles and usually more chemotherapy and radiation follows after surgery.

Lobular Carcinoma
About 12% of breast cancers start in lobules, which are situated at the end of each duct. Lobules are small grape-like clusters that produce milk. There are approximately 12-15 groups of lobules in each breast.

Lobular carcinoma is either "infiltrating or invasive" or "in-situ." In situ is usually a pre-cancerous situation and is not considered a malignancy. Infiltrating lobular carcinoma, however, is cancerous. Patients often describe it as a "thickening" of breast tissue, not a hard lump. The reason for this difference is that the cancerous cells do not form scar tissue as they grow; small finger-like projections are formed instead.

Because no lump exists, these cancers sometimes grow larger than ductal carcinomas before they are detected.

Paget's Disease of the Breast
Paget's disease of the breast is usually characterized by itching and scaling around the nipple. It is sometimes mistaken for eczema of the nipple, which is more common. A mammogram is done to make sure there is no cancer in the breast. Then a biopsy is performed on the skin of the nipple.

There are two variants of Paget's disease. In one, only the nipple is involved. In this case the nipple and areola (dark skin surrounding the nipple) are surgically removed. If the woman prefers, plastic surgeons can reconstruct the nipple. The other situation includes invasive cancer. If the area of invasion is a distance from the nipple, a mastectomy is done. If it is close to the nipple, a wide excision may be suggested, followed by radiation therapy.

Ductal Carcinoma in Situ (DCIS)
Ductal Carcinoma In Situ, or DCIS, is a very early stage of breast cancer. It is located entirely within the milk ducts of the breast; it does not penetrate the walls of the duct or the surrounding areas. It is considered cancer and must be treated.

These tumors appear as microcalcifications on a mammogram, representing tiny specks of calcium clustered within the breast. They usually cannot be felt on physical exam as a lump.

The pathology report will have the terms comedo or noncomedo, the former being the more serious. Comedo means that the cells filling the duct are more aggressive looking.

DCIS accounts for approximately 10% of all breast cancers. It requires treatment and is highly curable.

Lobular Carcinoma in Situ (LCIS)
Lobular Carcinoma In Situ, or LCIS, involves the milk-producing lobules. LCIS is not a cancerous condition, although it can develop into cancer in about 25% of women. LCIS does not show up on mammogram.

LCIS is considered a marker that cancer may develop later. Treatment for LCIS is controversial, and must be discussed with an oncologist or surgeon.