Dysplastic nevi are important to recognize because of an increased risk for development of malignant melanoma.
Clinical criteria for a dysplastic nevus:
(1) maximum diameter of 5 mm or more (one half unlike the other half)
(2) entirely flat, or having a flat component
(3) at least 2 of the following
(3a) variable pigmentation (color varies from one area to another)
(3b) irregular (scalloped or poorly circumscribed border), asymmetric (one half unlike the other half) outline
(3c) indistinct borders
Type and Number of Nevi |
Relative Risk for Developing Melanoma |
congenital nevi |
no increased risk |
increased number of small nevi (2-5 mm), without dysplastic nevi |
2-fold |
increased number of small and large nevi, without dysplastic nevi |
4-fold |
one dysplastic nevus |
2-fold |
10 or more dysplastic nevi |
12-fold |
Number of Nondysplastic Nevi |
Relative Risk for Developing Melanoma |
0 - 24 small (2 - 5 mm) |
1.0 |
25 - 49 small (2 - 5 mm) |
1.8 |
50 - 99 small (2 - 5 mm) |
3.0 |
>= 100 small (2 - 5 mm) |
3.4 |
1 large (> 5 mm) |
1.0 |
2 - 4 large (> 5 mm) |
1.3 |
5 - 9 large (> 5 mm) |
1.7 |
>= 10 large (> 5 mm) |
2.3 |
Number of Dysplastic Nevi |
Relative Risk for Developing Melanoma |
1 |
2.3 |
2-4 |
7.3 |
5-9 |
4.9 |
>= 10 |
12 |
Specialty: Dermatology, Hematology Oncology
ICD-10: ,