The most common is ductal carcinoma. This cancer begins in the lining of the milk ducts of the breast.
Lobular carcinoma is another type, which begins in the lobules where breast milk is produced.
Cancer cells can also break away from a malignant tumor and enter the bloodstream or the lymphatic system. This is how cancer spreads within the body. An important step in describing the extent of your breast cancer will be a step called staging. Knowing the exact stage of your disease will help your doctor plan your treatment. If the cancer is present in other parts of your body Once the lump and sample lymph nodes are removed they will go to a pathologist for testing and examination.