Breast Cancer Types
Understanding some of the key words used to describe various types of breast cancer is important. An alphabetical list of terms, including the most common types of breast cancer, is provided below:

Adenocarcinoma: This is a general type of cancer that starts in glandular tissues anywhere in the body. There are several subtypes of adenocarcinoma, which account for nearly all breast cancers.

Ductal carcinoma in situ (DCIS): DCIS is an uncommon type of breast adenocarcinoma in men. Cancer cells fill the ducts but do not invade through the walls of the ducts into the fatty tissue of the breast or spread outside the breast. It is almost always curable.

Infiltrating (or invasive) ductal carcinoma (IDC): Starting in a duct of the breast, this type of adenocarcinoma breaks through the wall of the duct and invades the fatty tissue of the breast. At this point, it can metastasize (or spread) to other parts of the body. IDC (alone or mixed with other types of invasive or in situ breast cancer) accounts for 80% to 90% of male breast cancers.

Infiltrating (or invasive) lobular carcinoma (ILC): ILC is a rare type of adenocarcinoma in men that arises from the ends of a man’s breast ducts.

In situ: This term describes an early stage of cancer in which a tumor is confined to the immediate area where it began. Specifically in breast cancer, in situ means that the cancer remains confined to ducts (ductal carcinoma in situ [DCIS]) or lobules (lobular carcinoma in situ [LCIS]), and it has neither invaded surrounding fatty tissue in the breast nor spread to other organs in the body. DCIS occurs relatively often in both men and women. In contrast, LCIS is common in women but very rare among men.

Metastases: These are satellite tumors of a breast cancer that has spread from the site where it began (referred to as the primary cancer) to a lymph node or a distant organ, such as the lung, liver, or brain.

Microcalcifications: These are small calcium deposits, often found in clusters by a mammogram. These deposits, sometimes called calcifications, are neither cancer nor tumors. They are signs of changes within the breast, and certain p