Understanding Your Pathology

What Is a Pathology Report?

After the biopsy is completed, the specimen is sent to a pathologist, a specially trained physician who interprets the nature of your lesion. Be sure to ask for a copy of your pathology report, even if you don’t want to read it. The attributes discussed in the pathology report, together with your physical examination, will usually provide an indication of what surgery is needed, whether you require additional, tests and therapy, and will help to indicate what the outcome of the disease is likely to be. Be sure to scroll down for the list of questions to ask about your pathology.

Here is an explanation of terms that may appear in your pathology report:

  1. Type: description of the particular variety of melanoma you have—superficial spreading melanoma, lentigo maligna melanoma, nodular melanoma, and so on. The superficial spreading type is the most common.
  2. Growth phase: designation that shows whether the melanoma has reached the step where it can grow as a lump below the epidermis. In the radial growth phase, as we have seen, it is unlikely that the cancer has begun to metastasize. With the vertical growth phase, there is at least some chance that the disease has spread elsewhere in the body.
  3. Mitotic count or mitosis: measure of how many melanoma cells are dividing below the epidermis. Only in the vertical growth phase do cells divide in the dermis. The higher the mitotic count, the more likely the tumor is to have spread.
  4. Tumor-infiltrating lymphocytes: immune system cells (lymphocytes) whose presence in the vertical growth phase are a positive sign. Presumably, lymphocytes show that the immune system has recognized the tumor and is attacking it.
  5. Greatest thickness: the Breslow thickness. A measurement of a millimeter or less is considered thin—and means a favorable prognosis.
  6. Site: location of the melanoma. Patients with a vertical growth phase melanoma located on an extremity have a relatively more favorable prognosis than those on the trunk or head and neck (a subtlety is that a rare subtype of melanoma that, unless the lesion appears on the palms, on the soles of the feet, or under the nails acts like trunk lesions).
  7. Sex: gender of the melanoma patient. For unexplained reasons, women have a better prognosis than men.
  8. Regression: An attribute that may be either absent or present in the radial growth phase (which is adjacent to the vertical growth phase). Regression is evidence of destruction (probably by immune factors) of some of the melanoma cells in the radial growth phase. Immunologically mediated regression of this sort is a weakly negative factor.
  9. Level of Invasion: the Clark level. Mine was a level IV tumor—that is, the melanoma had penetrated to just above the fatty layer of the skin.
  10. Precursor Lesion: Evidence of a pre-existing ordinary, dysplastic, or congenital mole from which the melanoma might have developed. My melanoma came from a dysplastic nevus. Although dysplastic nevi are the most common precursors, common moles and congenital moles may also be culprits. For many melanomas no evidence of a precursor shows up.

Questions to Ask Your Doctor About the Pathology Report

  1. Who will read the pathology? An expert dermatopathologist should probably be on hand if the lesion is difficult to identify or characterize.
  2. Will the doctor be available to discuss the pathology with me? The nurse may telephone you, if the biopsy shows that the growth is trivial (a seborrheic keratosis or an ordinary mole), but if it is more serious (say, a non-melanoma dysplastic mole, or melanoma), you should be able to consult personally with your physician.
  3. What exactly does this pathology mean? If it is melanoma, how do its attributes affect what additional tests I might have and what my prognosis is?
  4. What do you recommend as the next course of action?


Source: Melanoma: Not Just Skin Cancer, by Catherine M. Poole; Contributing editors: Keith Flaherty, MD, DuPont Guerry, MD and Jedd Wolchok, MD, 2015.

General Disclaimer

The MIF Website is designed for educational purposes only and is not engaged in rendering medical advice or professional services. The information provided through this Website should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, you should consult your health care provider.

UPDATED: September 1, 2018