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  • CAN and DN are clinicopathologic markers of patients at an increased risk for melanoma. Patients with CAN/DN should be screened regularly for melanoma.

  • CAN are not obligate precursors to melanoma, and they do not have to be removed—they may be clinically monitored for change.

  • The majority of melanomas are believed to arise de novo, and are not associated with a precursor nevus.

image Beginner Tips

  • A biopsy of a pigmented lesion is performed if there is a high level of suspicion for melanoma. Other reasons for biopsy may include irritation, cosmesis, or atypical lesions in areas difficult to self-monitor.

  • An excisional biopsy is the preferred method to remove any lesion concerning for melanoma to provide the most accurate diagnosis and smallest risk of recurrence.

image Expert Tips

  • Reexcisions need not be performed in mildly and moderately DN with clear margins on the original biopsy.

  • Mildly DN with positive histologic margins and no clinical residual pigmentation can be safely observed.

image Don’t Forget!

  • Observation of moderately DN with positive histologic margins and no clinical residuum may be reasonable, but more data are needed.

  • Severely DN with positive histologic margins should be reexcised.

image Pitfalls and Cautions

  • While the morbidity of a biopsy should always be considered, there is no substitute for biopsy in cases where a true concern for evolving melanoma exists.

  • Serial photography has no impact on the development of melanoma unless the clinician has a low threshold for biopsy for any evolving CAN.

image Patient Education Points

  • Patients should be taught that all CAN do not evolve on to melanoma, and that they represent a marker of melanoma risk rather than a “precancer.”

  • Therefore, most CAN may be monitored clinically as long as there is no evolution and they appear similar to the patient’s other CAN.

image Billing Pearls

  • The decision of whether to code a shave as a biopsy or shave removal is based on the surgeon’s intent. Even a deep, broad scoop shave, if performed to biopsy the lesion in question, should be coded as a biopsy.


Clinically atypical nevi (CAN)/dysplastic nevi (DN) are a subset of melanocytic nevi that clinically have an irregular, poorly defined border, asymmetric shape, and variegated pigmentation, and are generally larger than 5 mm.1 When biopsied, these lesions have certain histologic findings including disorganized melanocytic proliferations and associated atypical cells.2 Although CAN/DN themselves are not obligate precursors to melanoma, they are clinicopathologic markers of patients with an increased risk for melanoma.3,4 Some patients that have numerous CAN/DN can be challenging to follow clinically and may require surgical procedures for lesions suspicious for melanoma.


William Norris, a Scottish surgeon, reported the first case of cutaneous melanoma in 1820. He also ...

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