Atypical nevi (moles) are moles that are not melanoma (cancer) but are also not completely normal. Also known as dysplastic nevi (moles), atypical nevi are in a spectrum between completely normal moles and cancer, and we can grade them as MILD, MODERATE, or SEVERELY atypical.
Atypical nevi are seen on many individuals and are not related to sun exposure. Rather, these nevi are ones that you would get by genetics, and are not ones that you can prevent or stop. These nevi often look like other normal moles and are only diagnosed as atypical under the microscope. On the other hand, some atypical nevi look very suspicious and can resemble a melanoma. While your dermatologist may be able to spot an atypical nevus (e.g. abnormal mole), the diagnosis of an atypical nevus, and the degree of atypia (abnormal features), is only done under the microscope by an experienced dermatopathologist. An atypical nevus can be atypical in either the appearance of the cells (cellular atypia), or the organization of the cells (architectural atypia), or both.
The diagram below shows the spectrum of atypical nevi.
Mild Atypical Nevi – No treatment needed. These are very close to normal moles. Some dermatologists will excise every atypical nevi, even mild ones. Our practice does not excise mild atypical nevi.
Moderate Atypical Nevi – We recommend excision and closure of every nevus with moderate atypical features. We can never tell you what percent of these type of nevi ever change to melanoma, but we’d prefer not to leave you with that risk. We generally take out the biopsy scar plus 2mm of normal skin surrounding the scar. You will be left with stitches and a final line scar.
Severe Atypical Nevi – These are so close to melanomas that we recommend a WIDER excision and closure of every one of these nevi. Some dermatopathologists call these severe atypical nevi, but different dermatopathologists may even call the same lesion an early melonoma. We generally take out the biopsy scar plus 5mm of normal skin surrounding the scar. You will be left with stitches and a final line scar.