Table 1.

Summary of these criteria.

Dysplastic Nevus	Malignant Melanoma
Architectural criteria (mandatory, major)
Lentiginous or contiguous melanocytic hyperplasia	Poor circumscription of the intraepidermal melanocytic component of the lesion
Focal melanocytic atypia	Increased number of melanocytes, solitary and in nests, within and above the epidermal basal cell layer and within adnexal epithelia (pagetoid spreading)
	Marked variation in size and shape of the melanocytic nests
	Absence of maturation of melanocytes with descent into the dermis
	Melanocytes in mitosis
Architectural criteria (minor, at least 2)
“Shoulder phenomenon”	Melanocytes with nuclear atypia
Fusion of epithelial cones	Necrosis or degeneration of melanocytes
Subepidermal concentric lamellar fibrosis