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Atypical Melanocytic

Atypical melanocytic lesions are also known as dysplastic nevus or dysplastic mole, atypical mole, or atypical melanocytic hyperplasia. Mole and nevus are synonymous. By definition these lesions are benign. However, since this terminology is based on either a visual inspection or a partial biopsy of the lesion, the real diagnosis may be something more serious. Complete lesion excision and examination under a microscope is indicated.

HOW IS ATYPICAL MELANOCYTIC LESIONS DIAGNOSED BY VISUAL INSPECTION?

Five visual characteristics are used to identify an atypical melanocytic lesion. These are the same as the signs of invasive melanoma. These are called the ABCDE’s of melanoma.

  1. Asymmetry, one side of the mole is different from the other
  2. Borders that are irregular, blurred, or not even
  3. Color that is abnormally dark,different, or variable within a single lesion
  4. Diameter greater than 6 mm, a pencil eraser.
  5. Evolution of a mole's appearance, i.e. changes in color, size, or shape.

These signs require a biopsy of the lesion to rule out melanoma.

HOW IS ATYPICAL MELANOCYTIC LESION DIAGNOSED ON A BIOPSY?

Atypical melanocytic lesions are pigmented moles that have abnormal cells under a microscope. These lesions, once diagnosed as atypical with a partial skin biopsy, are typically excised to complete evaluation of remaining lesion, if some still remains. If the entire lesion was biopsied and removed initially, no further treatment is required. There is some controversy regarding excision of additional margins around a previous biopsy. Rationale for additional excision is to prevent the risk of melanoma developing in a few remaining abnormal cells. This is largely unproven but is frequently performed in the US.

Pathologists classify atypical melanocytic lesions as mild, moderate, or severe. Excision of additional margins should only be performed on the severely atypical lesions, if at all. In any of these classifications, complete lesion excision is necessary for the dermatopathologist to make a proper diagnosis. This is because within a single atypical pigmented lesion, significant variation of microscopic findings can be present. For example, a melanoma may be misdiagnosed as an atypical lesion if only a small periphery of it is biopsied.

Patients with multiple atypical melanocytic lesions proven on biopsies are at higher risk of developing melanoma in their lifetime. These patients require regular skin checks and frequent biopsies.

WHERE CAN I FIND OUT MORE INFORMATION ABOUT ATYPICAL MELANOCYTIC LESION TREATMENT?

If you are located in Orange County area and would like more information about atypical melanocytic lesion treatment options, contact us today.