Is invasive lobular carcinoma the same as invasive ductal carcinoma?

Different: Lobular carcinoma is less common and often does not form a lump. Please see these sites for more information. http://www.mayoclinic.com/health/invasive-lobular-carcinoma/ds01063 http://www.Mayoclinic.Com/health/breast-cancer/ds00328.

No. : These are the two most common types of breast cancer, named based upon their cell of origin: either from the lobules, where milk is made or ducts, thru which the milk passes to get to the nipple. Lobular ca tends to be less aggressive but is sometimes difficult to see by mammography & more prone to occur in both breasts. In general, the stage of the cancer is more important than the cell of origin.