When patients are diagnosed with breast cancer or other breast conditions, they may not always understand the terms used. There are several different kinds of breast cancer in addition to various other health conditions affecting the breasts. To better understand their breast health and to inform health care decisions, women should familiarize themselves with the anatomy of the breast and some breast-related health care terms.

Anatomy of the Breast

The female breast is mostly composed of adipose tissue, a type of connective tissue made up of fat cells. A network of lobes, lobules and ducts run through each breast. There are normally between 12 and 20 lobes within each breast and each lobule contains many smaller lobules. Lobules produce milk and ducts deliver milk to the nipple.

Cancers are often referred to by the part of the breast where they begin. A majority of breast cancers begin in the lobes, lobules and ducts. A very small percentage of breast cancers begin in connective tissue. Lobular breast cancer refers to cancers that begin in the lobules.

Invasive Lobular Carcinoma

The term ‘lobular breast cancer’ is usually made in reference to invasive lobular carcinoma (ILC). ILC is breast cancer that began in the lobules. When breast cancer is referred to as ‘invasive,’ it means the cancer spread into nearby breast tissue and potentially nearby lymph nodes.

Approximately 1 in 10 cases of invasive breast cancers are ILC. Invasive ductal carcinomas, which begin in the ducts of the breast, account for approximately 8 in 10 cases of invasive breast cancer.

Lobular Carcinoma In Situ

In women diagnosed with lobular carcinoma in situ (LCIS), abnormal cells have begun to grow within the lobules of the breast. However, abnormal cells are still confined to the lobules and have not spread to nearby breast tissue. LCIS is NOT cancer, although it does raise risk for developing cancer. Approximately 90 percent of lobular carcinoma in situ diagnoses occur in women who have not been through menopause.

LCIS may be described as ‘pleomorphic’ or ‘with necrosis.’ LCIS with necrosis means some of the abnormal cells are dead. Pleomorphic LCIS means abnormal cells appear significantly different from normal cells. LCIS with these features are associated with an even higher risk for developing invasive breast cancer.

Atypical Lobular Hyperplasia

Like LCIS, atypical lobular hyperplasia (ALH) is a noncancerous condition that involves the growth of abnormal cells within lobules. ALH is considered less severe than LCIS. However, it can progress to LCIS.

In cases of LCIS and ALH, abnormal cells are often identified first with a core needle biopsy sample after an abnormal finding on a mammogram. A surgical excisional biopsy is often recommended to further evaluate more tissue since 8-15% of cases of LCIS or ALH will be associated with an adjacent or occult malignancy. Women with either of these conditions may need to be monitored with increased surveillance. Consultation with a breast surgeon is essential. If you have been diagnosed with LCIS or ALH, you should speak with a physician about potential for supplemental screening and risk reduction.

At Breastlink, we are committed to ensuring patients understand their diagnoses, as well as the pros and cons of certain treatments. If you would like to learn more about lobular breast cancer, please contact us.

what is lobular breast cancer? | Orange County, CA breast health