Invasive lobular carcinoma is a type of breast cancer that begins in the milk-producing glands (lobules) of the breast.
Invasive cancer means the cancer cells have broken out of the lobule where they began and have the potential to spread to the lymph nodes and other areas of the body.
Invasive lobular carcinoma makes up a small portion of all breast cancers. The most common type of breast cancer begins in the breast ducts (invasive ductal carcinoma).
At its earliest stages, invasive lobular carcinoma may cause no signs and symptoms. As it grows larger, invasive lobular carcinoma may cause:
An area of thickening in part of the breast
A new area of fullness or swelling in the breast
A change in the texture or appearance of the skin over the breast, such as dimpling or thickening
A newly inverted nipple
Invasive lobular carcinoma is less likely than other forms of breast cancer to cause a firm or distinct breast lump.