TABLE 1.

ABCD-rule. The ABCD criteria were intended as a simple tool to alertnondermatologists to the clinical features of melanoma. The criteria were not meant toprovide a comprehensive list of all melanoma characteristics.

A	Asymmetry	Benign nevi are symmetric, their shape is round or oval. In contrast, cutaneous melanomas grow faster in several areas and are consequently asymmetric.
B	Border irregularity	Common nevi are bounded regularly to normal skin, whereas cutaneous melanomas often exhibit ragged and dull margins.
C	Color variegation	Benign nevi usually show homogeneous brown shade of color, whereas cutaneous melanomas exhibit different colors like black, brown, red or slate blue.
D	Diameter > 6 mm	After a growth period in infancy and adolescence, common nevi remain stable in size, whereas melanomas often grow rapidly. A diameter more than 6 mm is considered to be suspicious.