Lobular carcinoma in situ (LCIS) is a condition caused by unusual cells in the lobules of the breast

Breast

The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

.

It is usually not considered cancer

Cancer

Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, but it can indicate an increased risk of future cancer. Unlike Ductal Carcinoma in Situ (DCIS), LCIS is not associated with calcification

Calcification

Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification.-Causes:...

, and is typically an incidental finding in a biopsy performed for another reason.
Cells of LCIS and invasive lobular carcinoma

Invasive lobular carcinoma

Invasive lobular carcinoma accounts for 5-10% of invasive breast cancer.The histologic patterns include: Overall, the 5-year survival rate of invasive lobular carcinoma was approximately 85% in 2003....

 have the same histology

Histology

Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...

, appearing as single detached cells, as both have loss of expression of e-cadherin, the transmembrane protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 mediating epithelial cell adhesion

Cell adhesion

Cellular adhesion is the binding of a cell to a surface, extracellular matrix or another cell using cell adhesion molecules such as selectins, integrins, and cadherins. Correct cellular adhesion is essential in maintaining multicellular structure...

.