Atypical nevus syndrome in Child
The nomenclature regarding atypical nevi is confusing, but atypical melanocytic nevus (AMN), formerly referred to as atypical (dysplastic) nevus, is the most common term used today. Atypical nevus is also known as Clark nevus, atypical mole, B-K mole, and mole of FAMM (familial atypical mole and melanoma syndrome).
Common nevi are macular or papular symmetrical lesions that are smaller than 5 mm and have well-defined borders that are uniform in color. Atypical nevi, in contrast, have irregular colors and shapes and indeterminate borders. If one examined an isolated atypical nevus in a patient with atypical nevus syndrome, one would be suspicious for melanoma because of the striking irregular features of color, shape, and large size. At the onset, atypical nevi appear as ordinary small, symmetrical nevi, but they continue to grow over time – in contrast to other nevi – and develop blurred borders and asymmetry. Nevi may also appear atypical from the onset.
The risk of developing melanoma is related to a number of factors, which include:
- Number of ordinary nevi being more than 50-100 on the body.
- The presence of and number of atypical nevi.
The incidence of atypical nevus syndrome has been reported to be around 5%.
D23.9 – Other benign neoplasm of skin, unspecified
254819008 – Atypical mole syndrome
- Multiple common acquired melanocytic nevi
- Nevus spilus
- Melanoma – Differentiated from AMN by its larger size, greater asymmetry, and differing shades of pigmentation, which include blue-black, gray, brown, and tan, as well as a more irregular outline.
- Multiple lentigo syndromes, eg, Carney complex (NAME, LAMB)
- Xeroderma pigmentosum