Invasive lobular carcinoma, or ILC, accounts for about 10 to 15 percent of all breast cancers. Invasive means that it has "invaded" or spread to the surrounding tissues. It is called lobular because the cancer began in the lobules of the breast, which are the glands that produce milk. Carcinoma refers to any cancer that begins in the skin or other tissues that line or cover internal organs.
Lt Col Flemings
Invasive lobular breast carcinoma is not a more aggressive cancer than invasive ductal breast carcinoma, although this is a fairly common misconception. However, ILC is more frequently diagnosed in both breasts at the same time.