Tests to evaluate your condition may include:

  • Clinical breast exam and physical exam. During this exam, your doctor physically checks for unusual areas in both breasts, noting the appearance of the skin on and around your nipples and feeling for any lumps or areas of thickening.
  • Mammogram. A mammogram — an X-ray exam of your breast tissue — may indicate whether the nipple and skin changes are linked to an underlying breast cancer, as is usually the case in Paget's disease of the breast.

    If results from mammography in both breasts don't reveal any signs of breast cancer, your doctor may follow up with magnetic resonance imaging (MRI), which may detect cancer that's not able to be seen on a mammogram.

  • Breast biopsy. During a biopsy, your doctor obtains a small sample of tissue from the skin of your nipple for examination under a microscope. If you have nipple discharge, a sample of the discharge might also be collected.

    If you have a breast lump, a biopsy of that tissue will also be done. If cancer cells are detected in the samples collected, you may be referred to a breast surgeon to discuss treatment options.

  • Sentinel lymph node biopsy. If you have invasive breast cancer, the lymph nodes under your arm (axillary lymph nodes) need to be checked to see if the cancer has spread to this area. This can be done in a procedure known as a sentinel lymph node biopsy.

    During the biopsy, your surgeon locates the sentinel nodes — the first lymph nodes to receive the drainage from breast tumors and therefore the first place cancer cells will travel. If a sentinel node is removed, examined and found to be normal, the chance of finding cancer in any of the remaining nodes is small and no other nodes need to be removed.