To diagnose breast cancer, your doctor may order one or more of the following procedures:  

• Mammogram: An x-ray of the breast
• Ultrasound: A procedure that involves passing an instrument (transducer) over the breast tissue. The transducer sends out sound waves into the breast tissue. The sound waves bounce off tissue and create a picture of the breast tissue.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• Biopsy:  The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer. If a lump in the breast is found, the doctor may need to cut out a small piece of the lump. A pathologist views the tissue under a microscope to look for cancer cells. Four types of biopsies are as follows:
  • Excisional biopsy: The removal of an entire lump or suspicious tissue.
  • Incisional biopsy: The removal of part of a lump or suspicious tissue.
  • Core biopsy: The removal of part of a lump or suspicious tissue using a wide needle.
  • Needle biopsy or fine needle aspiration biopsy: The removal of part of a lump, suspicious tissue, or fluid, using a thin needle (click link at left for more).
• Estrogen and progesterone receptor test: A test on the hormones receptors (for estrogen and progesterone) receptors in cancer tissue. If cancer is found in the breast, tissue from the tumor is examined in the laboratory to find out whether estrogen and progesterone could affect the way cancer grows. The test results show whether hormone therapy may stop the cancer from growing. This test is often done as part of the pathology testing on a biopsy sample.