Dysplastic nevus other diagnostic studies

Overview

When an atypical mole has been identified, a biopsy takes place in order to best diagnose it. Local anesthetic is used to numb the area, then the mole is biopsied. The biopsy material is then sent to a laboratory to be evaluated by a Pathologist.

Biopsy

When an atypical mole has been identified, a skin biopsy takes place in order to best diagnose it. Local anesthetic is used to numb the area, then the mole is biopsied. The biopsy material is then sent to a laboratory to be evaluated by a pathologist. A skin biopsy can be a punch, shave, or complete excision. The complete excision is the preferred method, but a punch biopsy can suffice if the patient has cosmetic concerns (i.e. the patient does not want a scar) and the lesion is small. A scoop or deep shave biopsy is often advocated, but should be avoided due to risk of a recurrent nevus, which can complicate future diagnosis of a melanoma, and the possibility that resulting scar tissue can obscure tumor depth if a melanoma is found to be present and re-excised.

Most dermatologists and dermatopathologists use a system devised by the NIH for classifying melanocytic lesions. In this classification, a nevus can be defined as benign, having atypia, or being a melanoma. A benign nevus is read as (or understood as) having no cytologic or architectural atypia. An atypical mole is read as having architectural atypia, and having (mild, moderate, or severe) cytologic (melanocytic) atypia.[7] Usually, cytologic atypia is of more important clinical concern than architectural atypia. Usually, moderate to severe cytologic atypia will require further excision to make sure that the surgical margin is completely clear of the lesion.[citation needed]

The most important aspect of the biopsy report is that the pathologist indicates if the margin is clear (negative or free of melanocytic nevus), or if further tissue (a second surgery) is required. If this is not mentioned, usually a dermatologist or clinician will require further surgery if moderate to severe cytologic atypia is present – and if residual nevus is present at the surgical margin.