Breast Pathology

At UW Health in Madison, Wisconsin, your breast tissue sample will be reviewed by at least two pathologists who specialize in breast tissue. While pathologists often work behind the scenes from the patient's perspective, this doctor is a critical member of your care team.


The pathologist determines your diagnosis by looking at your breast tissue with a microscope. The pathologist reviews (reads) your breast biopsy as well as tissue from breast surgery and lymph node surgery. The pathologist’s diagnosis will determine which treatments are recommended for you.


Based on how your breast tissue cells look under the microscope, pathologist determines all the factors about your diagnosis.


Red video icon Watch our UW Health Breast Center leaders talk about the importance of pathology


Are your cells benign, atypical or malignant?

  • Benign: Normal breast tissue
  • Atypical: Different from normal breast tissue but not cancerous
  • Malignant: Cancerous cells

Is your cancer in situ or invasive?

  • In situ: Cancer cells are confined within the structures of the breast
  • Invasive: Cancer cells have moved outside the structures of the breast (ducts and lobules) and into surrounding breast tissue

What grade is your cancer?

  • Grade 1: Low grade, most like normal cells
  • Grade 2: Medium grade
  • Grade 3: High grade, cells are significantly different from normal cells

Is your cancer hormone-receptor positive?

  • ER positive: The cancer cells grow in response to estrogen
  • PR positive: The cancer cells grow in response to progesterone
  • HER2/Neu amplified: The cancer cells grow in response to human epidermal growth factor receptor proteins

Has cancer spread to your lymph nodes?

  • The pathologist will review lymph nodes removed during a sentinel lymph node biopsy or an axillary dissection and will report the number of nodes found to have cancer cells