The Grey Zone of Moles

When we are kids, we look at the world in terms of right or wrong, black or white, big or small.  We see only the absolutes.  It is only with life experience that we begin to appreciate that life is more grey than black or white. In time, we begin to understand that life falls along a spectrum, moving between the absolutes.

I often consider this concept as I explain moles, or pigmented lesions, to my patients.  Moles are growths on the skin made of nests of nevus cells and associated with the pigment from melanocytes.  Everyone has moles on their skin.  Some individuals have few, while others have many.  As a dermatologist, it is up to me to help patients observe and monitor their nevi in an attempt to identify melanoma skin cancers early.  So how do I break this task down into manageable pieces?

When I perform a skin examination, it is helpful to see the context of the patient’s entire skin.  This means having the patient disrobe. allowing me to look from head to toe.  As a “big picture”, I examine each mole and compare each mole or lesion to the others.  I think of this as the “ugly duckling” phenomenon.  It is reassuring when an individual’s spots match each other.  A lesion that stands out as different from the others can be concerning. 

As I look at each lesion, I keep in mind the “ABCD’s”.  This refers to asymmetry, borders, color, and diameter.  Each lesion should be even and symmetric in shape.  A lesion that is asymmetric can be worrisome.  The borders of moles should be smooth.  If I see notching or an uneven border, this catches my attention.  For color, I like to see uniform pigmentation throughout a mole.  I also like the patient’s moles to match each other.  In terms of diameter, I prefer that moles be less than 6 millimeters – roughly the size of a pencil eraser.  If I identify a lesion that is abnormal in any of these regards, it gives me reason to pause and consider whether a skin biopsy is necessary. 

In addition to the ABCD’s, I ask my patients if any of his or her moles are symptomatic.  Are any of the lesions itching, bleeding, or tender?  Is there a spot that for whatever reason continues to draw my patient’s attention?  If so, these lesions may require further examination and possible biopsy.

So, what is a biopsy?  A skin biopsy involves the removal of a small piece of skin tissue to analyze under the microscope.  The suspicious spot is numbed with an injection of lidocaine.  While the shot stings, the skin becomes numb in a few seconds.  Most biopsies are shave biopsies.  For these, a sharp blade is used to sample a thin piece of skin.  Shave biopsies heal in 1-3 weeks without stitches.  Sometimes, a punch biopsy is performed.  A punch biopsy is like a small cookie cutter.  Since a punch biopsy goes a little deeper in the skin, stitches are usually needed.  The tissue removed from either the shave or the punch biopsy is sent to our pathologist to examine under the microscope.  It typically takes about a week to receive the biopsy results. 

The report that I receive from my pathologist gives a diagnosis and a microscopic description of the lesion.  In the case of moles, the pathologist reports whether the lesion is a benign nevus, a dysplastic nevus, or melanoma.  I think of these as a spectrum.  Benign moles or nevi are normal.  They are not worrisome.  On the opposite end of the spectrum is melanoma, a serious form of skin cancer.  Dysplastic or atypical nevi represent the grey zone between the absolutes of benign moles and melanoma.  To help guide appropriate treatment, our pathologists grade the atypical nevi as mild, moderate or severe.  Mildly atypical nevi are only slightly different from a benign nevus and typically do not require any further removal.  Moderately atypical nevi are more abnormal.  In managing these lesions, I prefer to completely excise these lesions.  Severely atypical nevi are closer to the “melanoma neighborhood” and require complete excision. 

Once excised, the tissue is sent again to the pathologist.  The specimens are examined under the microscope to verify that clear margins have been achieved.  Going forward, patients with atypical nevi are at increased risk for melanoma.  I recommend that these individuals have a full body skin examination annually.  In addition, I encourage patients to perform a self-examination of the skin once monthly.  Regular self-exams make it easier for individuals to recognize changes in moles.  Photographs can be helpful in monitoring moles, too. 

Skin lesions can vary greatly in size, shape and color.  Knowing the extremes between normal moles and melanoma makes it easier to judge which lesions require biopsy and possible excision.  With this in the balance, it is always best to rely upon a board-certified dermatologist to help negotiate the grey zones of the spectrum between normal moles and skin cancer. 

Author

Jane Lisko, MD Dr. Lisko is a board-certified dermatologist. She has practiced at Associated Skin Care Specialists, PA in Eden Prairie, MN, and Fridley, MN, since 2001. Dr. Lisko specializes in skin cancer diagnosis and surgery, cosmetic dermatology, and laser surgery. She is married to Dr. Jeff Lisko, a gastroenterologist. Together they have four sons. When not working or spending time with her family, Dr. Lisko enjoys traveling, reading, exercising on her Peloton bike, and playing golf (poorly but with a smile!)